Effects of CBCT acquisition protocol and additional superimposed computerized optical impressions on the accuracy of root canal length measurements: an ex vivo study.

AIM: The purpose of the present investigation was to evaluate the accuracy of root canal length (RCL) determination according to CBCT acquisition protocol and evaluate the influence of additional superimposed computerized optical impressions. MATERIALS AND METHODS: CBCT scans with low-dose (LD) and high-definition (HD) protocols as well as computerized optical impressions of 30 extracted human molars were acquired. Sicat Endo software (Sicat) was used for CBCT RCL measurements with (LD+, HD+) and without (LD-, HD-) a superimposed optical impression. To evaluate the accuracy, absolute differences between test groups and the actual root canal length (ARCL) were calculated and statistically analyzed using the Wilcoxon rank sum test. RESULTS: Absolute differences between the ARCL and the tested measurement methods varied significantly (P < 0.05). Both higher resolution and additionally superimposed computerized optical impression improved measurement accuracy. Mean differences compared with the ARCL were 0.26 mm (HD+), 0.34 mm (HD-), 0.43 mm (LD+), and 0.66 mm (LD-). 93.4% of all measurements in the HD+ group were within the limits of ± 0.5 mm. CONCLUSION: Both resolution and superimposition of additional computerized optical impressions have a significant influence on RCL measurements using CBCT.

Apical periodontitis after intense bruxism.

BACKGROUND: Bruxism is known to cause masticatory muscle pain, temporomandibular joint pain, headaches, mechanical tooth wear, prosthodontic complications and cracked teeth. Less known to the practitioner, and described only experimentally in literature, is that bruxism can also damage the pulp. To our knowledge, this is the first known clinical case of a patient developing apical periodontitis due to bruxism. CASE PRESENTATION: This article presents the case and successful treatment of a 28-year-old healthy male patient with apical periodontitis on teeth 36 and 46 requiring root canal treatment after an intense phase of bruxism. Due to an unclear diagnosis, treatment had been delayed. CONCLUSIONS: Incomprehensible tooth pain can be the result of bruxism. Practitioners need to be informed that intense bruxism can possibly lead to apical periodontitis. It is important, therefore, that a thorough anamnesis is collected and taken into account during diagnostics.

Guided endodontic access of a calcified mandibular central incisor using a software-based three-dimensional treatment plan.

This case report describes the digital and clinical workflow of a guided endodontic access approach in a mandibular central incisor with pulp canal calcification (PCC). The access to the remaining pulp space was planned virtually using cone beam computed tomography (CBCT) and the Sicat Endo software (Sicat, Bonn, Germany). Sicat produced the corresponding Accessguide after matching a digitized cast model and the virtual treatment plan. The clinical access was prepared using a carbide bur with a diameter of 1.2 mm. After the root canal was localized successfully, it was disinfected chemomechanically, dried, and obturated using a warm vertical compaction technique.

The use of computer-assisted FACE for minimal-invasive caries excavation.

OBJECTIVES: Caries excavation is still a demanding procedure today. In the past years, methods using light-induced fluorescence have proven their ability to detect bacteria remaining in the tooth's hard tissues. However, methods to control the complete removal of infected dentine have not yet been validated. The aim of the present study was to evaluate the degree of dentine removal during caries excavation using a camera- and software-based device as a guide for fluorescence-aided caries excavation (FACE) in comparison to visual-tactile inspection and a dye-staining method. MATERIALS AND METHODS: One hundred teeth with carious lesions (C3) were randomly allocated to four groups and excavated with the respective method as primary excavation control method. When the first method indicated complete caries excavation, a second method was used to affirm this. Subsequently, dentine samples were taken to determine residual contamination using PCR. After embedding and sectioning the teeth dentine, microhardness was measured perpendicular to the cavity floor. RESULTS: By using the camera- and software-based device, 94 % of the cavities tested were free of bacterial contamination. All cavities excavated with the dye-staining or visual-tactile control method were free of bacterial contamination but resulted in a significantly higher dentine removal. CONCLUSION: The camera- and software-assisted caries excavation seems to be an adequate method to remove contaminated dentine without removing affected dentine. CLINICAL RELEVANCE: Beside its original application to monitor carious, the device is safe, effective, and easy to use for guided caries excavation and is of worth for both everyday practice and undergraduate education.

Effect of photodynamic therapy (PDT) on Enterococcus faecalis biofilm in experimental primary and secondary endodontic infections.

BACKGROUND: To determine the antibacterial effect of photodynamic Therapy on Enterococcus faecalis (E. faecalis) biofilms in experimentally infected human root canals in primary infections and endodontic retreatments. METHODS: One hundred and sixty single-rooted extracted teeth with one root canal were prepared using ProTaper instruments. Seventy specimens were left without root canal filling and autoclaved. The root canals of another 70 specimens were filled with Thermafil and AH Plus and the root canal fillings were removed after 24 hours using ProTaper D files and plasma sterilized. The specimens were infected with a clinical isolate of E. faecalis for 72 hours. Samples were taken using sterile paper points to determine the presence of E. faecalis in the root canals. The specimens were randomly divided into groups according to their treatment with 20 teeth each and a control. In the PDT group the teeth were treated using PDT, consisting of the photosensitizer toluidine blue and the PDT light source at 635 nm. In the NaOCl (sodium hypochlorite) group the root canals were rinsed with 10 mL of 3% NaOCl. In the NaOCl-PDT group the root canals were rinsed with 10 mL of 3% of sodium hypochlorite and then treated with PDT. Samples were taken after treatments using sterile paper points. Additionally, remaining root canal filling material was recovered from the root canal walls. Survival fractions of the samples were calculated by counting colony-forming units. A one-way analysis of variance (ANOVA) was applied to the data to assess the effect of different treatment techniques. RESULTS: Antimicrobial treatment of root canals caused a significant reduction of bacterial load in all groups. NaOCl irrigation eliminated E. faecalis most effectively. PDT alone was less effective compared to NaOCl irrigation and the combination of NaOCl irrigation and PDT. CFU levels recovered from the filling material after NaOCl irrigation of the root canals were 10fold higher compared to PDT and the combination of NaOCl irrigation and PDT. CONCLUSIONS: Photodynamic therapy killed E. faecalis in experimental primary endodontic infections and retreated human root canals. PDT is an effective supplement in root canal disinfection, especially in endodontic retreatments.

Comparison between two thermoplastic root canal obturation techniques regarding extrusion of root canal filling--a retrospective in vivo study.

OBJECTIVES: The aim of this study was to compare two different thermoplastic techniques--a core-carrier technique (Thermafil) and warm vertical compaction--in terms of overextension of root canal filling in vivo. MATERIALS AND METHODS: Flaring of 88 teeth was conducted using Pro Files .04 as finishing files, and the teeth were obturated using Thermafil. Flaring of 74 teeth was performed using Pro Files .06 as finishing files, and the teeth were obturated using warm vertical compaction. RESULTS: Seventy (80 %) of the teeth obturated using Thermafil and 31 (42 %) teeth obturated using warm vertical compaction show extruded root canal filling. In contrast to Thermafil, there is a higher rate of extruded root canal filling of teeth with more than one root canal using warm vertical compaction. CONCLUSION: Thermafil demonstrated a higher rate of extruded root canal filling compared to warm vertical compaction. Warm vertical compaction is a more predictable method of filling compared to Thermafil. CLINICAL RELEVANCE: Root canal filling extrusion will cause irritation of the surrounding tissue and impair repair processes. In the present in vivo study, there was a higher rate of root canal filling extrusion using Thermafil compared to warm vertical compaction.

Biodentine Inhibits the Initial Microbial Adhesion of Oral Microbiota In Vivo.

This study aimed to evaluate the in vivo initial microbial adhesion of oral microorganisms on the biomaterial Biodentine compared to MTA and AH Plus. Cylindrical samples of the materials were prepared, and dentin slabs served as a control. An individual intraoral lower jaw splint served as a carrier for the samples and was worn by six volunteers. The specimens were worn for 120 min. Adherent bacteria were quantified by determining the colony-forming units (CFUs), while the visualization and quantification of total adherent microorganisms were facilitated by using DAPI and live/dead staining combined with fluorescence microscopy. Bovine dentin had a significantly higher number of aerobic CFUs compared to Biodentine (p = 0.017) and MTA (p = 0.013). The lowest amounts of DAPI-stained adherent microorganisms were quantified for Biodentine (15% ± 9%) and the control (18% ± 9%), while MTA showed the highest counts of initially adherent microorganisms (38% ± 10%). Significant differences were found for MTA and Biodentine (p = 0.004) as well as for MTA and the control (p = 0.021) and for AH Plus and the control (p = 0.025). Biodentine inhibited microbial adherence, thereby yielding an antimicrobial effectivity similar to that of MTA.

The evaluation of fluorescence changes after application of casein phosphopeptides (CPP) and amorphous calcium phosphate (ACP) on early carious lesions.

PURPOSE: To evaluate the effect of casein phosphopeptides (CPP) and amorphous calcium phosphate (ACP), as an adjunct to average oral hygiene, on the fluorescence of initial carious fissures and pits in vivo. METHODS: For this investigator-blind in vivo study 32 volunteers were recruited. Subjects with premolars and molars showing DIAGNOdent-values between 15 and 20 were randomly assigned to two treatment groups. During a wash-out period of 2 weeks and during the 3-week treatment period all subjects were instructed to use only standard fluoride toothpaste (1450 ppm F- as NaF) and to abstain from any oral hygiene products other than dental tape. During the treatment period, one group additionally applied a CPP-ACP containing cream on the respective fissures for 3 minutes, once per day. At Days 1, 8, 15, and 22, DIAGNOdent measurements and a visual assessment of the fissures were performed by two calibrated independent examiners. RESULTS: No significant changes of DIAGNOdent values were found in the control group during the study period. Fissures additionally treated with the CPP-ACP containing cream showed significantly lower laser fluorescence values after Day 15 (P = 0.001) and Day 22 (P < 0.001) compared to the control group. No significant difference in the visual classification between the two groups could be found.

Comparison of in vitro fluoride uptake from whitening toothpastes and a conventional toothpaste in demineralised enamel.

Studies on the compatibility of abrasives and fluoride compounds deal exclusively with fluoride uptake and remineralization after storing the enamel specimens in a toothpaste-saliva mixture. The influence of brushing on the fluoride uptake when highly abrasive toothpastes are used has hardly been investigated so far. The aim of the present study was to investigate fluoride uptake in initially demineralised dental enamel after storage in, or brushing with, whitening toothpaste slurries, compared to a conventional toothpaste. For this purpose two widely available whitening toothpastes with ionically bound fluoride (sodium fluoride NaF), two with covalently-bound fluoride toothpastes (sodium monofluorophosphate, NaMFP) and a conventional amine fluoride toothpaste (AmF) were compared. The fluoride uptake after use of the AmF toothpaste was shown to be statistically significantly higher than that after application of the NaF toothpastes, which in turn was statistically significantly higher than the uptake resulting from NaMFP application. The fluoride uptake was slightly higher when the enamel samples were brushed with NaF toothpaste, rather than just stored in the respective toothpaste slurry. Brushing with highly abrasive toothpastes did not negatively influence fluoride uptake in demineralised dental enamel. The ionic form of the fluoride in toothpastes appears to be critical for increased fluoride uptake. The acidic components of the AmF toothpaste improved fluoride uptake compared to alkaline NaF toothpastes.

Comparison of the efficacy of different Ni-Ti instruments in the removal of gutta-percha and sealer in root canal retreatment.

AIMS: To evaluate and compare the efficacy of four rotary instrumentation systems in root canal retreatment and to determine retreatment time. MATERIALS AND METHODS: To achieve the purpose of this study, canals of 60 distal roots in mandibular molar teeth were selected and randomly divided into four groups A, B, C and D (n = 15). Using step-back technique, the canals were prepared and filled with gutta-percha and AH Plus employing cold lateral compaction technique. The root filling material was removed with the following retreatment systems: Group A: Mtwo R, group B: D-RaCe, group C: ProTaper R and group D: R-Endo. In order to record retreatment time, a stopwatch was used. The samples were split longitudinally, examined under a stereomicroscope, photographed and assessed with AutoCAD software. Finally, the percentages of remaining filling material were calculated and the extracted data were analyzed using one-way ANOVA and Tukey HSD test. RESULTS: All examined groups showed traces of remaining filling material within the canals. No statistically significant difference was found among the four groups in the coronal, middle, and apical thirds. The same result was obtained with regard to retreatment time (P > 0.05). However, within each one of the groups, significant difference was observed in the three regions (P < 0.05). CONCLUSIONS: Based on the findings of this study, none of the examined systems could completely remove root filling material from the root canals. However, they were all found to be effective in this regard. The most amount of remaining filling material was found in the apical third.

Effect of adhesive resin cements and post surface silanization on the bond strengths of adhesively inserted fiber posts.

This study evaluated the tensile bond strengths and the effect of silanization of fiber posts inserted with different adhesive systems. Sixty DT Light Posts (size 1) were used. Thirty posts were pretreated with silane. The posts were cemented into form-congruent artificial root canals (12 mm) of bovine dentine. Six groups were formed: G1, Prime&Bond NT/Calibra; G2, Monobond-S+Prime&Bond NT/Calibra; G3, ED Primer/Panavia 21ex; G4, Monobond-S+ED Primer/Panavia 21ex; G5, RelyX Unicem; and G6, Monobond-S+RelyX Unicem. The mean (standard deviation) tensile bond strengths (megapascals) were 7.69 (0.85) for G1, 7.15 (1.01) for G2, 6.73 (0.85) for G3, 6.78 (0.97) for G4, 4.79 (0.58) for G5, and 4.74 (0.88) for G6. G1 achieved significantly higher bond strengths than G3 and G5; G3 had significantly higher values than G5 (P < .05; Scheffé procedure). Silanization had no significant effect (P > .05, one-way analysis of variance). Tensile bond strengths were significantly influenced by the type of resin cement. Silanization of fiber post surfaces seems to have no clinical relevance.

Remineralization of artificial interproximal carious lesions using a fluoride mouthrinse.

PURPOSE: To evaluate remineralization and fluoride uptake of demineralized enamel specimens in artificial interproximal spaces using a 250 ppm fluoride mouthrinse (100 ppm amine fluoride and 150 ppm sodium fluoride) compared to a placebo-mouthrinse. METHODS: This was a two-way, double-blind, in situ study. 24 volunteers wore intraoral appliances in the lower jaw with mounted demineralized enamel specimens forming an artificial interproximal space. The volunteers rinsed their mouths for 28 days, twice a day with the respective mouthrinse and brushed their teeth at least twice a day with a fluoride-free dentifrice. The specimens were cleaned once a day to simulate the use of dental floss. For analysis methods transversal microradiography, fluoride content measurement and quantitative light-induced fluorescence were used. RESULTS: Mineral gain was significantly higher after the use of the fluoride mouthrinse: 571.88 Vol.% x microm (+/- 79.33 Vol.% x microm SEM) compared to the placebo treatment 51.14 Vol.% x microm (+/- 72.14 Vol.% x microm SEM). Significantly more fluoride uptake was observed after using the fluoride mouthrinse: 3666.39 microg/cm3 (+/- 513.50 microg/cm3 SEM) than after the placebo mouthrinse: 516.95 microg/cm3 (+/- 75.83 microg/cm3 SEM). The quantitative light-induced fluorescence showed a significant remineralizing effect after the fluoride treatment: -388.47 % x mm2 (+/- 18.76% x mm2 SEM) compared to the placebo treatment -27.88% x mm2 (+/- 20.19% x mm2 SEM).

Influence of adhesive systems on bond strength between fiber posts and composite resin cores in a pull-out test design.

The aim of this study was to evaluate the effects of post surface conditioning with adhesive systems on tensile bond strength between two composite resin core systems and FRP posts (ER DentinPost). Forty-eight posts were trimmed at the coronal part, and the upper part of 3 mm was covered with a standardized composite resin core build-up. Twenty-four posts were treated with the respective adhesive systems. Four groups were formed: G1 - ClearfilCore; G2 - Clearfil New Bond + ClearfilCore; G3 - MultiCore Flow; and G4 - AdheSE + MultiCore Flow. Mean (SD) bond strengths in MPa were 7.53 (0.89) for ClearfilCore and 8.08 (0.93) for New Bond + ClearfilCore; 5.80 (0.39) for MultiCore Flow and 5.92 (0.43) for AdheSE + MultiCore Flow. ClearfilCore achieved significantly higher bond strengths than MultiCore Flow (two-way ANOVA; p<0.0001). In conclusion, composite resin core materials exerted a significant influence on tensile bond strength, while adhesive systems did not significantly affect the results.

[Enamel microabrasion and in-office bleaching for fluorosis: a case report]. / Schmelzmikro-abrasion und In-Office-Bleaching bei Fluorose. Ein Fallbericht.

Enamel microabrasion is a proven method of removing superficial intrinsic enamel discoloration defects from teeth. In many cases, with insignificant and unrecognizable loss of enamel, those defects can be permanently eliminated, improving the appearance of treated teeth. This article describes the treatment of one patient whose fluorotic brown stains were corrected with a combination of enamel microabrasion and in-office-bleaching technique with a hydrogen peroxide gel solution.

Comparison of two cone-beam computed tomography systems in the visualization of endodontic structures.

An important part of endodontic diagnosis and treatment is the adequate visualization of root canal anatomy. The objective of the present study was to compare two different three-dimensional cone-beam computed tomography (CBCT) systems, Scanora 3D and 3D Accuitomo 170, with respect to their visualization of endodontic canal systems and potential pathological alterations. Seventy extracted human teeth were investigated with regard to the radiographic detection of number of root canals, lateral canals, root canal fillings and posts, vertical root fractures, and the occurrence of image artifacts. For each evaluation parameter under investigation the radiographic diagnoses obtained by the two different CBCT systems under investigation were similarly accurate, without statistically significant differences. The evaluation of teeth containing highdensity foreign materials was impaired for both CBCT systems because of image artifacts. However, a difference between the CBCT systems was not observed. In conclusion, both CBCT systems were found to be similarly suitable for the visualization of endodontic structures in vitro.