Merete Markvart

Treatment of deep caries lesions in adults: randomized clinical trials comparing stepwise vs. direct complete excavation, and direct pulp capping vs. partial pulpotomy

Less invasive excavation methods have been suggested for deep caries lesions. We tested the effects of stepwise vs. direct complete excavation, 1 yr after the procedure had been carried out, in 314 adults (from six centres) who had received treatment of a tooth with deep caries. The teeth had caries lesions involving 75% or more of the dentin and were centrally randomized to stepwise or direct complete excavation. Stepwise excavation resulted in fewer pulp exposures compared with direct complete excavation [difference: 11.4%, 95% confidence interval (CI) (1.2; 21.3)]. At 1 yr of follow-up, there was a statistically significantly higher success rate with stepwise excavation, with success being defined as an unexposed pulp with sustained pulp vitality without apical radiolucency [difference: 11.7%, 95% CI (0.5; 22.5)]. In a subsequent nested trial, 58 patients with exposed pulps were randomized to direct capping or partial pulpotomy. We found no significant difference in pulp vitality without apical radiolucency between the two capping procedures after more than 1 yr [31.8% and 34.5%; difference: 2.7%, 95% CI (-22.7; 26.6)]. In conclusion, stepwise excavation decreases the risk of pulp exposure compared with direct complete excavation. In view of the poor prognosis of vital pulp treatment, a stepwise excavation approach for managing deep caries lesions is recommended.

Micro-CT analyses of apical enlargement and molar root canal complexity

AIM To compare the effectiveness of two rotary hybrid instrumentation techniques with focus on apical enlargement in molar teeth and to quantify and visualize spatial details of instrumentation efficacy in root canals of different complexity. METHODOLOGY Maxillary and mandibular molar teeth were scanned using X-ray microcomputed tomography. Root canals were prepared using either a GT/Profile protocol or a RaCe/NiTi protocol. Variables used for evaluation were the following: distance between root canal surfaces before and after preparation (distance after preparation, DAP), percentage of root canal area remaining unprepared and increase in canal volume after preparation. Root canals were classified according to size and complexity, and consequences of unprepared portions of narrow root canals and intraradicular connections/isthmuses were included in the analyses. One- and two-way anova were used in the statistical analyses. RESULTS No difference was found between the two techniques: DAP(apical-third) (P = 0.590), area unprepared(apical-third) (P = 0.126) and volume increase(apical-third) (P = 0.821). Unprepared root canal area became larger in relation to root canal size and complexity, irrespective of the technique used. Percentage of root canal area remaining unprepared was significantly lower in small root canals and complex systems compared to large root canals. The isthmus area per se contributed with a mean of 17.6%, and with a mean of 25.7%, when a narrow root canal remained unprepared. CONCLUSIONS The addition of isthmuses did not significantly alter the ratio of instrumented to unprepared areas at total root canal level. Distal and palatal root canals had the highest level of unprepared area irrespective of the two instrumentation techniques examined.

Randomized Clinical Trials on Deep Carious Lesions: 5-Year Follow-up:

Deep caries presents a dilemma in terms of which treatment that will render an optimal prognosis by maintaining pulp vitality with absence of apical pathology. Previously, 2 randomized clinical trials were performed testing the short-term effects of stepwise carious tissue removal versus nonselective carious removal to hard dentin with or without pulp exposure. The aim of this article was to report the 5-y outcome on these previously treated patients having radiographically well-defined carious lesions extending into the pulpal quarter of the dentin but with a well-defined radiodense zone between the carious lesion and the pulp. In this long-term study, 239 of 314 (76.2%) patients were analyzed. The stepwise removal group had a significantly higher proportion of success (60.2%) at 5-y follow-up compared with the nonselective carious removal to hard dentin group (46.3%) (P = 0.031) when pulp exposures per se were included as failures. Pulp exposure rate was significantly lower in the stepwise carious removal group (21.2% vs. 35.5%; P = 0.014). Irrespective of pulp exposure status, the difference (13.3%) was still significant when sustained pulp vitality without apical radiolucency and unbearable pain was considered (95% confidence interval, 3.1–26.3, P = 0.045). After pulp exposure, only 9% (n = 4) of the analyzed patients were assessed as successful, indicating that the prognosis is highly dubious following conventional pulp-capping procedures (direct pulp capping or partial pulpotomy) in deep carious lesions in adults. In conclusion, the stepwise carious removal group had a significantly higher proportion of pulps with sustained vitality without apical radiolucency versus nonselective carious removal of deep carious lesions in adult teeth at 5-y follow-up (ClinicalTrials.gov NCT00187837 and NCT00187850).

Quality-Shaping Factors and Endodontic Treatment amongst General Dental Practitioners with a Focus on Denmark

There is a gap between the endodontic outcome that can be achieved and the outcome observed on the basis of worldwide general dental practitioner data. The quality of root canal treatment (RCT) is shaped by the dentists knowledge, attitude, and skills, but it may also be influenced by the patients demands and degree of satisfaction. The topic has only been sparsely investigated. Although dental health has increased over the years in Denmark, the number of performed root fillings has also increased, probably because the number of tooth extractions have declined and more molar teeth have been treated. Caries appears to be the main cause for performing RCT and a preventive approach by employing stepwise excavation may reduce RCT, but this strategy does not remove the gap. Factors influencing RCT quality could be the status on adoption of nickel-titanium rotary technology, more focus on infection control (rubber dam use, knowledge of factors important for prognosis), as dentists often think that they are good at doing RCT, but often perform inadequately, an alteration of clinicians awareness of their performance in the context of dental practices, seems warranted. Finally, the development of new preventive modalities for pulp and apical inflammation are crucial.

Three-dimensional analysis of the pulp cavity on surface models of molar teeth, using X-ray micro-computed tomography

Abstract Aim. The purpose of this study was to investigate the scanning and segmentation precision of surface models of molars for the detection of small volumes, such as the reduced pulp cavity; formation of mineral deposits; detection of narrow root canals and to improve the clinical and morphological understanding of the number of root canals and their configuration. Methods. Eighteen human molars were scanned using X-ray micro-computed tomography. The reconstruction of the surface models had a precision of <1 voxel, using three-dimensional software and quantitative color mapping. In order to relate the measurements to changes over time the size of the pulp chambers was classified in two well-defined groups. Results. The mineral deposits were more evenly distributed in small pulp chambers than in large, but complete root canal calcification was never observed. No difference was observed in the material with respect to the presence of intra-radicular connections. In upper molars, a second mesiobuccal canal (mb2) frequency of 91% was found. The difference in length between the first mesiobuccal canal (mb1) and mb2 was <1 mm. The number of root canals could be related to the number of root cones. Conclusion. In summary, three-dimensional surface models were made with a high precision; an increased accumulation of mineral deposits was noted in molars with small pulp chambers and combined with the consistent pattern of intra-radicular connections, the potential endodontic treatment complexity is underlined in such cases. Finally, an improved understanding of root canal prevalence was reached, when merging well-defined definitions on root morphology and clinical classification systems.

Comparison of UVB and UVC irradiation disinfection efficacies on Pseudomonas Aeruginosa ( P. aeruginosa ) biofilm

Disinfection routines are important in all clinical applications. The uprising problem of antibiotic resistance has driven major research efforts towards alternative disinfection approaches, involving light-based solutions. Pseudomonas aeruginosa (P. aeruginosa) is a common bacterium that can cause skin, soft tissue, lungs, kidney and urinary tract infections. Moreover, it can be found on and in medical equipment causing often cross infections in hospitals. The objective of this study was to test the efficiency, of two different light-based disinfection treatments, namely UVB and UVC irradiation, on P. aeruginosa biofilms at different growth stages. In our experiments a new type of UV light emitting diodes (LEDs) were used to deliver UV irradiation on the biofilms, in the UVB (296nm) and UVC (266nm) region. The killing rate was studied as a function of dose for 24h grown biofilms. The dose was ramped from 72J/m2 to 10000J/m2. It was shown that UVB irradiation was more effective than UVC irradiation in inactivating P. aeruginosa biofilms. No colony forming units (CFU) were observed for the UVB treated biofilms when the dose was 10000 J/m2 (CFU in control sample: 7.5 x 104). UVB irradiation at a dose of 20000J/m2 on mature biofilms (72h grown) resulted in a 3.9 log killing efficacy. The fact that the wavelength of 296nm exists in daylight and has such disinfection ability on biofilms gives new perspectives for applications within disinfection at hospitals.

The antimicrobial effect of apical box versus apical cone preparation using iodine potassium iodide as root canal dressing: A pilot study

Abstract Purpose. The purpose was to study the reduction of intra-canal microflora in premolars with apical periodontitis instrumented with either apical box or apical cone preparation and to provide measurements of intervention effects to allow proper power calculation in future clinical trials. Methods. Twenty-four patients were centrally randomized to apical box preparation (size #60) or cone preparation (apical size #25). The groups were comparable regarding the presence of primary caries and type of coronal restoration. In the course of canal preparation each tooth was irrigated with 2.5% NaOCl (12 ml). Lastly, the canals were filled with 17% EDTA (2 × 30 s) and 5% iodine potassium iodide (IKI) for 10 min. The canals were sampled for micro-organisms on four occasions: before instrumentation, after instrumentation, after application of IKI dressing and at the beginning of the second appointment 1 week later. Between the treatment sessions, the root canals were sealed with IRM cement. In the laboratory, culture techniques were used to measure microbial growth, which was classified as: none, very sparse, sparse, moderate, heavy or very heavy. Results. Initially, microbes were recovered in 88% of the teeth. Growth was classified as none in 35% of the teeth after instrumentation and in 50% after the application of IKI. Irrespective of the time of sampling, no significant difference in microbial growth reduction was observed between the two types of apical preparation. Based on the 1-week post-sampling, a power calculation revealed that over 900 patients are needed to show a difference of 9% between the two protocols tested. Conclusions. Future trials should be conducted using stringent protocols and as multi-centre trials for reaching the required information size.

Maxillary Sinus Impaction of a Core Carrier Causing Sustained Apical Periodontitis, Sinusitis, and Nasal Stenosis: A 3-year Follow-up

INTRODUCTION The aim was to present a case report of a full-length extrusion of an obturators core carrier into the maxillary sinus, causing clinical symptoms from the nose region with differential diagnostics aspects, which, in turn, led to several surgical treatments of the nostrils before diagnosis and correct endodontic retreatment of a maxillary right first molar. A 36-year-old man presented in 2012 with complaints from the right nostril region. Medical treatment with antibiotics and surgical procedures because of nasal stenosis resulted only in partial improvement. Five years earlier, a root canal treatment was performed on the maxillary right first molar. Intraoral radiographs revealed 10-mm overfilling of root filling material into the maxillary sinus from the palatal root of tooth #3. METHODS Before surgical removal of the excess root filling material, orthograde revision was performed. Cone-beam computed tomographic imaging was used to localize the position of the root filling material, which protruded through the maxillary sinus and reached the inferior nasal wall. RESULTS Surgical removal from the palatal aspect revealed that the root filling material was a core carrier of an obturator. Scanning electron microscopy and transmission electron microscopy showed evidence of microbial biofilm on the core carrier as well as remnants of sinus mucosa. At the long-term follow-ups, the tooth had healed apically, and symptoms of nasal stenosis were markedly reduced. CONCLUSIONS This case report represents a challenging differential diagnostic topic urging the importance of a medical and dental interdisciplinary dialogue. The use of cone-beam computed tomographic imaging was crucial for the surgical retreatment.

Ten-year follow-up on adoption of endodontic technology and clinical guidelines amongst Danish general dental practitioners

Abstract Objective: The aim of this study was to re-assess the adoption of certain endodontic technology and central treatment principles of root canal treatments as advocated by guidelines presented by the European Society of Endodontology. Material and methods: The questionnaire included the same questions in 2003 and 2013. The general dental practitioners (GDPs) anonymously reported how frequent (‘often’, ‘occasionally’, and ‘never’) they used certain endodontic technology and adhered to central treatment principles. The statistical analyses were performed using Chi-squared test and Goodman–Kruskal’s γ-coefficient as an association measure. Results: The overall response rate of the 2013 group was 46.5% (n = 531). The frequencies of GDPs reporting often use of rubber dam, apex locator and rotary NiTi instruments were significantly higher (p < .0001) than in 2003, as well as reporting the use of composite resin for coronal sealing (p < .019). Adoption was significantly influenced by the factors gender (p = .601) and time since graduation (p = .361), and the cluster analyses revealed the neglected use of rubber dam to be associated with no established postoperative recall system. Conclusions: After 10 years, there was a higher frequency of GDPs who had adopted certain endodontic technologies. However, progress towards high-quality root canal treatment might be obstructed as the majority of GDPs avoids consistent use of rubber dam, and routinely neglects recalls for postoperative controls of their endodontic treatments.

Light assisted antibiotics

The overuse of antibiotics is accelerating the bacterial resistance, and therefore there is a need to reduce the amount of antibiotics used for treatment. Here, we demonstrate that specific wavelengths in a narrow range around 296 nm are able to eradicate bacteria in the biofilm state more effectively, than antibiotics and the combination of irradiation and antibiotics is even better, introducing a novel concept light assisted antibiotics. The investigated wavelength range was 249 nm to 338 nm with an approximate step of 5 nm. The novel concept can significantly reduce the amount of antibiotics needed for eradicating mature bacterial biofilms. The irradiation treatment was combined with tobramycin and its efficiency was compared to combinatory antibiotic treatment and highly concentrated antibiotic monotherapy. The eradication efficacies, on mature biofilms, achieved by light assisted antibiotic and by the antibiotic monotherapy at 10-fold higher concentration, were equivalent. The present achievement could motivate the development of light assisted antibiotic treatments for treating infections.