Efficacy of endodontic applications of ozone and low-temperature atmospheric pressure plasma on root canals infected with Enterococcus faecalis.

UNLABELLED: This study aimed to compare the antimicrobial efficacy of low-temperature atmospheric pressure plasma (LTAPP) design and gaseous ozone delivery system with 2.5% NaOCl on Enterococcus faecalis in root canal walls and dentine tubules. The samples were divided into LTAPP (n = 12), ozone (n = 12), NaOCl (positive control, n = 12) and saline (negative control, n = 6) groups. Microbial samples were collected using paper points and dentin chips from root canals. Antimicrobial efficacy was assessed by counting the colony-forming units of Ent. faecalis before and after each irrigation protocol. Data were analysed using Kruskal-Wallis, Wilcoxon signed-rank, Friedman and Bonferroni t (Dunn's test)-tests (P = 0.05). The microbial sampling with paper points showed antibacterial efficacy of NaOCl, LTAPP, ozone and saline in descending order, respectively (P < 0.05). The microbial sampling with dentin chips demonstrated a superior efficacy of LTAPP compared with NaOCl in the middle third (P < 0.05), while both had similar effects in coronal and apical thirds (P > 0.05). NaOCl and LTAPP were better than ozone at the coronal and middle parts of the root canals (P < 0.05). These findings led us to suggest that LTAPP, which has no thermal and chemical effects, may be of great aid in endodontic treatment. SIGNIFICANCE AND IMPACT OF THE STUDY: The present study handles different perspectives on chemomechanical preparation of root canals. Ozone and low-temperature atmospheric pressure plasma (LTAPP) were investigated to determine whether they could be an alternative for NaOCl. Up to now, chemical solutions (NaOCl, chlorhexidine digluconate, etc...) have been used to disinfect the root canals. When the reported effects of LTAPP on biological and chemical decontamination were taken into consideration, a question rose whether it has antimicrobial efficacy in root canals infected with E. faecalis. According to the findings of the present study, LTAPP may constitute a promising aid in endodontics in disinfection of root canals.

A retrospective radiographic study of coronal-periapical status and root canal filling quality in a selected adult Turkish population.

OBJECTIVE: To investigate the oral health (with regard to the periapical status, quality of root fillings and coronal restorations) in an urban adult Turkish subpopulation using digital panoramic radiographs. MATERIALS AND METHODS: One thousand digital panoramic radiographs involving 28,000 teeth were selected from the archive of the Public Oral and Dental Health Center of Isparta. Coronal status (the type of restoration, signs of marginal leakage or decay), root filling quality (length and lateral seal) and periapical status (according to Periapical Index, PAI) were evaluated. Correlations between apical periodontitis (AP) and the quality of root fillings or coronal restorations were statistically analyzed using the χ(2) test. RESULTS: Of the 28,000 teeth evaluated, 22,380 (80.0%) were sound, 4,732 (16.9%) were missing, 753 (2.6%) were filled and 135 (0.5%) were decayed. Of the 753 coronal restorations, 400 (53.1%) were radiographically acceptable. Of the 23,268 teeth, 601 (2.6%) were root filled and 247 root fillings were adequate. Ninety-five (15.8%) root-filled teeth had AP (PAI 3-5). Out of the total, the AP prevalence was 0.4% in root-filled teeth and 0.8% in teeth without root fillings. The presence of AP was significantly correlated with inadequate coronal restorations and root canal fillings (p = 0.000). CONCLUSION: Tooth type, quality and type of coronal restorations, and length and homogeneity of root fillings significantly affected periapical status.

A comparison of the efficacy of conventional and new retreatment instruments to remove gutta-percha in curved root canals: an ex vivo study.

AIM: To compare the efficacy of conventional and new retreatment instruments when removing gutta-percha root fillings in curved root canals. METHODOLOGY: A total of 56 curved molar roots were instrumented with ProFile instruments and filled using system B and Obtura II. The root fillings were removed with manual K-files and Hedström files (Dentsply Maillefer), ProFile (Dentsply Maillefer), R-Endo (Micro-Mega) or ProTaper Universal retreatment files (Dentsply Maillefer). Eucalyptol was used as a solvent with all techniques. Bucco-lingual and proximal radiographs of the roots were exposed and the percentage area of the remaining material was calculated by dividing the area of remaining filling material by the area of canal wall. Data were statistically analysed with Kruskal-Wallis and Mann-Whitney U tests (P = 0.05). RESULTS: None of the techniques completely removed the root filling materials. No significant differences were found amongst the coronal, middle and apical thirds in both radiographic projections (P > 0.05). In the bucco-lingual direction, the remaining filling material was significantly less following manual instrumentation than R-Endo and ProTaper instrumentation (P < 0.05). In the proximal view, it was significantly less following manual and ProFile instrumentation than R-Endo (P < 0.05). Complete removal of filling material occurred only in three specimens (with manual instruments). Manual instruments were significantly faster than R-Endo and ProFile (P < 0.05). More procedural errors (five fractured instruments and two perforation) were noted when using ProTaper (P < 0.05). CONCLUSIONS: In this laboratory study in curved molar roots, ProTaper Retreatment and R-Endo instruments were less effective in removing filling material from canal walls than manual and ProFile instruments.

Micropush-out bond strengths of gutta-percha versus thermoplastic synthetic polymer-based systems - an ex vivo study.

AIM: To compare the interfacial strength and failure mode of root fillings consisting of different technique-material combinations. METHODOLOGY: Human mandibular premolars (n = 144) instrumented to apical size 40 and .06 taper were divided into 12 experimental groups. The root canals were filled with either gutta-percha (groups 1-6) or Resilon (groups 7-12) core materials combined with AH Plus (groups 1, 4, 7, 10), Ketac-Endo (groups 2, 5, 8, 11) or Epiphany (groups 3, 6, 9, 12) using cold lateral compaction (groups 1-3, groups 7-9) or System B with Obtura II (groups 4-6, groups 10-12). Three serial 1.00 +/- 0.05-mm-thick root slices were prepared and push-out tests on the filling material were performed. Interactions amongst the compaction techniques, core materials and sealers were analysed using a three-way analysis of variance (anova) (P < 0.05). One-way anova and Duncan's Multiple Range tests were used to compare the bond strengths of the 12 groups. Fracture modes of all root slices were evaluated stereomicroscopically at x40 magnification. RESULTS: All the parameters except compaction techniques had significant interactions (P < 0.05). A significant difference was found amongst the groups (P < 0.05). Gutta-percha/Ketac-Endo/cold lateral compaction and gutta-percha/AH Plus/cold lateral compaction groups had the highest micropush-out bond strength values (P < 0.05). The number of overall cohesive failures was significantly more than that of adhesive failures (P < 0.05). CONCLUSIONS: The push-out bond strengths of Resilon/Epiphany combinations were lower than those of gutta-percha/conventional root canal sealer combinations. Core materials and sealers may affect the push-out bond strengths of root canal filling materials.

Comparison of cold lateral compaction and continuous wave of obturation techniques following manual or rotary instrumentation.

AIM: To compare different combinations of root canal preparation and obturation technique. METHODOLOGY: A total of 48 freshly extracted human maxillary central incisors were divided into two identical groups on the basis of root canal length and apical diameter. The root canals were prepared by manual crown-down pressureless technique or with a rotary system (ProFile; Dentsply Maillefer, Ballaigues, Switzerland) in a crown-down technique. The coronal diameter and apical size of the root canals were standardized in both preparation techniques. Each main group was then divided into two subgroups and obturated with either cold lateral compaction or continuous wave of obturation with System B (EIE-Analytic Technology, Orange, CA, USA). The distribution of filling material in each canal was assessed by stereomicroscopic examination of eight cross-sections on each tooth. Areas of sealer, gutta-percha and voids were measured on the digital images of a total of 384 samples. Manipulation time and apical extrusion for each group was also determined. Data were statistically analysed using Kruskal-Wallis, anova (Bonferroni/Dunn) or Student's t-test. RESULTS: The percentage of sealer, gutta-percha and voids area between the obturation techniques was not significantly different (P > 0.05). Continuous wave groups had significantly more apical extrusion of sealer (P < 0.05), while none of the obturation techniques had gutta-percha extrusion. Rotary instrumentation was significantly faster than the manual technique (P < 0.05); continuous wave obturation was significantly faster than lateral compaction (P < 0.05). Total manipulation time in the rotary/continuous wave group was significantly shorter than the other groups (P < 0.0001). CONCLUSION: The distribution of filling materials was similar in all combinations of instrumentation and obturation techniques. The continuous wave technique was faster than lateral compaction and it extruded more sealer.

Paraneoplastic retinopathy associated with metastatic cutaneous melanoma of unknown primary site.

PURPOSE: To describe further the clinical and immunological features of cutaneous melanoma-associated retinopathy, which is an infrequent form of paraneoplastic syndrome. METHODS: We studied the salient clinical and immunological aspects of a 66-year-old man with metastatic cutaneous melanoma to lymph nodes of unknown primary site who developed melanoma-associated retinopathy. RESULTS: There was gradual loss of vision in the left eye. Colour vision and night vision were not affected. Visual fields showed arcuate defects. A full-field electroretinogram demonstrated attenuation of the b-wave amplitude in the left eye. The a-wave was intact. Indirect immunofluorescence techniques showed that the antibody reactions took place mainly in the outer plexiform layer of the retina. CONCLUSIONS: Bipolar cells seem to be the target in melanoma-associated retinopathy. Contrary to previous reports, night blindness may not be a universal finding.