Shaping and Centering Ability, Cyclic Fatigue Resistance and Fractographic Analysis of Three Thermally Treated NiTi Endodontic Instrument Systems.

The better understanding of the clinically important behavioral features of new instrument systems has an important significance for the clinical endodontics. This study aimed to investigate the shaping and centering ability as well as cyclic fatigue resistance of HyFlex CM (CM), HyFlex EDM (EDM) and EdgeFile (EF) thermally treated nickel-titanium (NiTi) endodontic instrument systems. Sixty curved root canals of the mesial roots of mandibular molars were randomly assigned into three groups (n = 20) and shaped using CM, EDM and EF files up to the size 40 and taper 04 of the instruments. µCT scanning of the specimens before and after preparation was performed and the morphometric 2D and 3D parameters were evaluated in the apical, middle and coronal thirds of root canals. In each group, 40.04 instruments (n = 20) were subjected to the cyclic fatigue resistance test in artificial root canals at 37 °C temperature until fractures occurred, and the number of cycles to failure (NCF) was calculated. The fractographic analysis was performed using a scanning electron microscope, evaluating topographic features and surface profiles of the separated instruments. The one-way analysis of variance with post hoc Tuckey's test was used for statistical analysis of the data; the significance level was set at 5%. All systems prepared the comparable percentage of root canal surface with the similar magnitude of canal transportation in all root thirds (p > 0.05), but demonstrated significantly different resistance to cyclic fatigue (p < 0.05). The most resistant to fracture was EF, followed by EDM and CM. The length of the fractured fragments was not significantly different between the groups, and fractographic analysis by SEM detected the typical topographic features of separated thermally treated NiTi instrument surfaces.

Potential to induce dentinal cracks during retreatment procedures of teeth treated with "Russian red": An ex vivo study.

OBJECTIVE: The aim of this study was to compare the impact of treatment procedures on roots previously treated with resorcinol-formaldehyde resin and analyze the effectiveness of dye and magnification for the detection of dentin cracks. MATERIALS AND METHODS: Distal roots of 80 permanent first mandibular molars with a single canal were sectioned at 3mm and 9mm from the anatomical apex. Two groups were formed according to the method used for root canal penetration: group 1 (K-file and Pro Taper instruments) and group 2 (Ultrasound with Pro Ultra and Pro Taper files). Before and after the completion of procedures, photographs of the roots were taken for examination for cracks or/and infraction lines with two levels of magnification and with or without a dye. RESULTS: In groups 1 and 2, either with dye or without it, there were statistically significant differences (P<0.001) with more fractures observed in the coronal than in the apical part of specimens. Statistically significant proportional differences regarding the location of fractures were observed at both magnifications. When the dye was used, there were no statistically significant differences between the two magnifications in the detection of cracks. In the specimens where the dye was not used, differences between the groups were statistically significant at both magnifications with more complete and intra-dental fractures observed in group 2. CONCLUSIONS: Retreatment methods had a damaging effect on the root dentin of teeth previously treated with resorcinol-formaldehyde resin. At magnification ×16, the efficacy of using the dye for the detection of cracks was higher than detection without the dye.

The appearance of root canal surfaces in teeth previously treated using resorcinol-formaldehyde resin: a preliminary SEM investigation.

OBJECTIVE: To evaluate the root canal surfaces in teeth previously treated using RF resin by SEM. MATERIAL AND METHODS: 20 distal roots of mandibular molars with typical discoloration of tooth crown were used in this study: 10 brownish - red and 10 non-colored roots. The roots were removed from the crowns, splinted longitudinally and subjected to SEM in a back-scattered electron mode. RESULTS: In discolored root samples canal walls appeared without smear layer and varying amount of remaining debris, the observed morphology of dentine was ordinary. In the non-colored root samples the dentin profile revealed: in coronal third of the root just few open dentinal tubules were detected, while in the middle and apical thirds no open dentinal tubules were observed, dentin profile was similar to sclerotic dentin. The multiple dentinal defects were detected in all samples, however significantly more dentinal defects were found in the colored roots. The RF paste was well adhered to the root canal dentine and multiple tags of RF resin penetrating deeply into the dentinal tubules were detected. CONCLUSIONS: The surfaces of the root canal walls of the teeth treated using RF paste exhibits usual appearance and ordinary dentin morphology in colored roots while the dentin of non-colored samples has the profile of sclerotic dentin. Multiple dentinal defects could be determined by damaging effect of RF resin on dentin. The adaptation and adhesion of RF paste to the dentin, capability to penetrate into dentinal tubules is comparable with the modern resin based sealers.

Pain and flare-up after endodontic treatment procedures.

Flare-ups can occur after root canal treatment and consist of acute exacerbations of an asymptomatic pulpal and/or periradicular pathologic condition. The causative factors of interappointment pain encompass mechanical, chemical, and/or microbial injury to the pulp or periradicular tissues. Microorganisms can participate in causation of interappointment pain in the following situations: apical extrusion of debris; incomplete instrumentation leading to changes in the endodontic microbiota or in environmental conditions; and secondary intraradicular infections. Interappointment pain is almost exclusively due to the development of acute inflammation at the periradicular tissues in response to an increase in the intensity of injury coming from the root canal system. The mechanical irritation of apical periodontal tissue is caused by overinstrumentation of the root canal and filling material extrusion through the apical foramen. Incorrectly measured working length of the root canal has inherent connection with these causative factors of endodontic flare - up. This review article discusses these many facets of the flare-up: definition, incidence causes and predisposing factors.

Technical aspects of endodontic treatment procedures among Lithuanian general dental practitioners.

OBJECTIVE: The purpose of this study was to gather information about the various aspects, technical and biological, of endodontic treatment as performed by Lithuanian general dental practitioners and to compare their choices with established endodontic treatment standards of undergraduate education. MATERIALS AND METHODS: Questionnaires were sent to all 2,850 Lithuanian dental practitioners. The structured questionnaire included inquiries about gender, duration of professional activity, working environment, details about instruments and materials. RESULTS: From total 1532 (53.8%) questionnaires were returned. Only responses from general dental practitioners (1431) were included. Of the respondents 66% never used a rubber dam. Most practitioners relied on conventional stainless steel instruments. The NiTi hand files were often and routinely used by 32.2% of the respondents. Sodium hypochlorite was the most popular choice as a root canal irrigant. Calcium hydroxide paste was used as an inter-appointment medicament. Cold-lateral condensation root filling method was used by 72.8% of the respondents while 15.6% used a paste for the root filling. CONCLUSIONS: The results of this study indicate that the recently graduated dental practitioners were following the recommended standard of endodontic treatment better than those with a longer time from the graduation. It is important to improve the quality of existing courses of continuous education in endodontology in order to ensure the necessary competency in clinical practice. The low use of a rubber dam and low adoption of new technologies in Lithuania is not acceptable and needs to be changed.

The need and reasons for referrals to specialists among Lithuanian general dentists.

OBJECTIVE: To analyze the need for referral to a specialist and to identify the reasons of referrals among Lithuanian general dental practitioners. MATERIAL AND METHODS: Questionnaires were sent to all 2879 Lithuanian dental practitioners registered on the Lithuanian Dental Chamber license registry. The questionnaire was made with multiple-choice answers. Respondents were asked to choose only one category of answer that best fitted their clinical attitude. Questions included in the questionnaire concerned general and specific information regarding the need and main reasons for endodontic referral. RESULTS: Of the 2879 questionnaires mailed, 1532 questionnaires containing useful information were returned. The response rate was 53.2%. Of the 1532 respondents, 1431 were general dental practitioners. Majority (72.1%) of the respondents performed complicated root canal treatment by themselves. Almost half (49.6%) of them would like to refer patients to an endodontist. Two of the reasons, which restricted their decision, were the shortage of endodontists and high cost of the procedures in the specialized clinics. Approximately 19% of the respondents referred patients to an endodontist. The main reasons for referral were fractured instruments (86.6%), dental trauma (83.6%), difficulties in diagnostics (79%) followed by persistent symptoms (78.1%). CONCLUSION: The findings of the present study suggest that the need for referral of patients to an endodontist among Lithuanian dental practitioners exists. The main reasons for referrals were complications of endodontic treatment, traumatic injuries, difficulties in diagnostic procedures, and persistent symptoms.

Antibiotic prescription for the treatment of endodontic pathology: a survey among Lithuanian dentists.

OBJECTIVE: To describe a pattern of antibiotic prescription during root canal treatment procedures based on the reports of Lithuanian general dental practitioners. MATERIALS AND METHODS: Questionnaires concerning endodontic treatment were sent to all 2850 Lithuanian dental practitioners registered on the database of the Lithuanian Dental Chamber. Only the questions containing general information and individual decisions about antibiotic prescription for endodontic treatment were selected for the analysis. RESULTS: The response rate was 53.8%. Of the 1532 responses, 1431 questionnaires received from licensed general dental practitioners were analyzed. More than 60% of the respondents reported prescribing antibiotics in cases of symptomatic apical periodontitis. Majority of the respondents (83.9%) reported symptomatic apical periodontitis with periostitis being a clear indication for the prescription of antibiotics. Nearly 2% of the respondents reported prescribing antibiotics in cases of symptomatic pulpitis. With an increasing duration of professional activity, an increase in the proportion of the respondents reporting prescription of antibiotics was observed. Amoxicillin was the most preferable antibiotic during endodontic treatment, followed by amoxicillin with clavulanic acid. An increase in reporting penicillin prescription and decline in prescribing amoxicillin and amoxicillin with clavulanic acid with regard to the increasing age of respondents was observed. CONCLUSIONS: Lithuanian dentists, particularly those with longer duration of professional activity, tended to exceed general recommendations for the antibiotics prescription in cases of endodontic infections. However, a trend toward prescription of broader spectrum antibiotics by younger dentists, compared with those with longer professional activity, was observed.

Attitudes of general dental practitioners towards endodontic standards and adoption of new technology: literature review.

Research data regarding attitudes of general dental practitioners towards endodontic therapy is rare. The present review summarizes existing literature and analyzes human factors that could potentially influence the outcome of endodontic treatment in general dental practice. Root canal treatment usually fails when treatment falls short of acceptable standards. The results of questionnaire surveys from several countries indicate that differences between daily general practice and academic teaching exist. The results of studies indicated that majority of general practitioners disregard the most basic principles of endodontic treatment. The most striking finding is the generally negative attitude amongst general dental practitioners towards performing endodontic treatment and adoption of new technologies in a daily endodontic practice. The results confirm that root canal treatment is technically demanding and in general practice is carried out under less than optimal conditions. This review shows the importance of continuous dental education for practitioners in order to update their knowledge.

In vitro study of microbial leakage in roots filled with EndoREZ sealer/EndoREZ Points and AH Plus sealer/conventional gutta-percha points.

OBJECTIVE: The aim of this study was to determine and compare the microbial leakage of roots filled with EndoREZ sealer/EndoREZ Points and AH Plus sealer/ conventional gutta-percha points. MATERIALS AND METHODS: 60 single-rooted teeth were prepared using step-back technique. The smear layer was removed with 18% EDTA. Teeth were divided into two experimental groups (n=25 each group) and two controls (n=5 each group). In AH Plus group root canals were obturated with AH Plus sealer/gutta-percha and in EndoREZ group with EndoREZ sealer/EndoREZ Points. Five teeth were served as negative controls and five as positive controls. All teeth were inserted into Eppendorf plastic tubes and suspended in glass bottles containing sterile Schaedler broth. The coronal chambers were filled with the mix of human saliva and broth (ratio 3:1). The medium was changed every 7 days. Microbial growth in the broth was evaluated every day up to the end of experiment. RESULTS: Leakage in the root canals of the teeth from experimental groups occurred between 4 and 75 days. The mean leakage in AH Plus group was 18.86 days, while in EndoREZ group it was 28.28. No statistically significant difference in microbial leakage between two tested filling materials was found. CONCLUSION: Both types of root fillings - EndoREZ sealer/EndoREZ Points and AH Plus sealer/gutta-percha points - showed microbial leakage.

Relationship between mandibular cortical bone height and bone mineral density of lumbar spine.

UNLABELLED: The aim of this study was to evaluate the association between lumbar spine bone mineral density and mandible cortical bone height at the mental foramen and at the angle of the jaw. PATIENTS AND METHODS: A total of 130 women living in Lithuania, were examined. None of the participants were known to have endocrine, metabolic or skeletal disorders. Bone mineral density (BMD) was measured in the spine lumbar area L2-L4. The mandibles were examined on panoramic x-ray images. On each radiograph cortical thickness of mandible was measured at the mental foramen and at the angle of the jaw. The results demonstrated a tendency of high probability of osteoporosis in cases were radiomorphometric parameters are low. There was a significant difference between bone mineral density of lumbar spine and cortical bone height of mandible below the foramen mentale and at the angle of the jaw (p<0.01).

Microorganisms in root canal infections: a review.

A traditional concept is that apical periodontitis is the result of pathogenic effects of the microorganisms colonizing the root canal system and the response of the host defence system. The composition of the microflora of root canals differs in primary endodontic treatment and retreatment cases. Persistent disease in the periapical region after root canal treatment presents a more complex situation as it was thought earlier. Scientific evidence indicates that unsatisfactory outcome of cases in which treatment has followed the highest technical standards mainly is associated with microbial factors, comprising extraradicular and/or intraradicular infections.

Factors influencing the removal of posts.

UNLABELLED: Root canal retreatment in teeth restored with intraradicular posts has attracted interest due to the difficulties of their removal without weakening, perforating or fracturing the remaining root structure. The use of ultrasonic devices has been suggested by some authors to facilitate post removal, reducing the possibility of fractures or root perforations. The purpose of this study was to determine the efficacy of cast posts removal by ultrasonic device regarding post length, adaptation of post to root canal walls and cement type. MATERIAL AND METHODS: Seventy-seven single rooted endodontically treated teeth restored with cast posts were included to this study. Post removal was processed with ultrasonic and time for this was recorded. The length and width of the post, quality of post adaptation, type of cement were evaluated according to radiographic findings and clinical records. RESULTS: Mean value of time needed for post removal was 14.15 (SD +/- 8.57) minutes. A strong correlation was observed between the time of post removal and post length (r=0.620, p=0.000). The mean time required for the removal of posts cemented with zinc phosphate was 11.36 min (SD +/- 5.84) and for the posts cemented with resin modified glass-ionomer was 15.37 min (SD +/- 3.83). Statistically significant difference in the time needed for the posts cemented with different cements was observed (p = 0.002). The mean time needed for the post removal with the inappropriate adaptation was 10.1 min (SD +/- 6.0) and the time for the post with appropriate adaptation was 15.7 min (SD +/- 8.9). Statistically significant difference between these two groups was observed for the time of posts removal (p = 0.003). According to the results of linear regression model test, 50% of variation in time needed to remove posts was explained by following variables: post length, post adaptation and the cement type. The total regression model was highly significant (p = 0.000). CONCLUSIONS: The time taken for post removal depended on post length, its adaptation in the root canal and on the type of luting cement. Root fractures are unlikely to occur with good case selection.