Effect of operators' proficiency level and patients' related factors on possible complications, using a high frequency polyamide sonic intracanal irrigation device: A prospective clinical cohort study.

OBJECTIVES: Sonic/ultrasonic devices are essential tools in today's endodontics. This prospective trial evaluated for the first time the impact of practitioners' proficiency levels and patient-related factors on complications associated with a high frequency polyamide sonic irrigant activation device. METHODS: In total 334 patients (females:158, males:176; age:18-95 years) received in the course of their endodontic therapy an intracanal irrigation, using a high frequency polyamide sonic irrigant activation device, by practitioners of different proficiency levels (undergraduate students, general practitioners or endodontists). Intracanal bleeding (yes/no), postoperative pain (0-10 scale), emphysema (yes/no) and polyamide tip fractures (yes/no) were recorded and related to proficiency levels, age, gender, tooth type, smoking-status, systemic conditions affecting healing ability, baseline pain, swelling, fistula, sensitivity to percussion and diagnosis. RESULTS: Intracanal bleeding was associated with patients' age (p<0.05), baseline pain level (OR = 1.14, 95%CI = 0.91-1.22) and baseline swelling (OR = 2.73, 95%CI = 0.14-0.99; p<0.05) but not proficiency level, gender, tooth type, smoking, systemic conditions, baseline fistula or sensitivity to percussion (p>0.05). Postoperative pain development was related to proficiency level (p<0.05) and baseline pain level (p<0.001), with no influence of age, gender, tooth type, smoking, systemic conditions, baseline fistula, swelling or sensitivity to percussion (p>0.05). Emphysema and polyamide tip fractures were not reported. CONCLUSIONS: Within the current study's limitations, younger patients with higher baseline pain and swelling, were associated with higher intracanal bleeding. Apart from higher postoperative pain observed with less experienced practitioners, proficiency level had no influence on bleeding, polyamide tip fracture or emphysema, endorsing the high frequency polyamide sonic irrigation device as a safe therapeutic device.

2D radiographs, cone-beam computed tomography and 3D CBCT-based planning software in access cavity preparation: A single blinded randomised controlled in vitro study.

This study compared endodontic access cavities prepared by operators of different experience levels (students, general-practitioners and specialists), guided by periapical radiographs, cone-beam computed tomography (CBCT) or 3D CBCT-based planning software, with regards to tooth substance loss and preparation errors. Operators (n = 34) prepared endodontic access cavities in 306 three-dimensionally printed copies of human teeth with standardised anatomies. Access cavities were volumetrically assessed post-operative using digital scans, while preparation errors were evaluated with CBCT. Tooth substance loss was significantly influenced by the operator's experience, being highest with students', followed by general-practitioners and specialists (P < 0.05), with no significant association with the employed imaging/planning modality. Pulp chamber floor, iatrogenic perforations and incomplete pulpal roof removal were insignificant between operator groups or imaging/planning modalities. It can be concluded that irrespective of advancement in imaging/planning modalities the practitioner's experience level remains to be the decisive factor significantly influencing tooth substance loss during endodontic access cavity preparations.

Assessment of Different Root Canal Preparation Techniques with Rotary Nickel-Titanium Instruments by Novice Students.

This study investigated which preparation strategy for root canals leads to the best technical preparation quality, and moreover, which is perceived to be performed best by novice students. Sixty-four students were recruited to prepare one simulated root canal with each of the following: FlexMaster files (F), Mtwo files (M), and Reciproc files (R). After preparation, the students assessed the different instrument systems through a questionnaire. The technical quality of the root canal preparations was evaluated by the centering ratio of the preparation. A total of 186 prepared root canals were submitted for evaluation. With R, significantly better centered preparations were achieved when compared to M and F (p < 0.001). The students evaluated R faster than M and F, and evaluated F significantly (p < 0.05) slower than R and M. M was rated as the easiest system to learn and to handle, as well as the best at reaching the working length; therefore, it was evaluated as the overall favorite of the students. A difference was found between the students' perceptions and their achieved technical quality of root canal preparations.

The accuracy of the auto-stop function of different endodontic devices in detecting the apical constriction.

BACKGROUND: Electronic apex locators (EALs) are modern devices used to determine the working length during root canal preparation. The newest endodontic motors provide an integrated EAL with auto-stop function to prevent instrumentation beyond the predefined working length during rotary root canal preparation. The aim of this study was to compare the accuracy of the auto-stop function of the VDW.Gold RECIPROC motor (VDW, Munich, Germany), the EndoPilot motor (Schlumbohm, Brokstedt, Germany) and the manual measurement with Raypex 6 (VDW, Munich, Germany) to detect the apical constriction (AC). METHODS: Ninety human teeth were chosen and randomly assigned to three experimental groups (30 teeth each): VDW.Gold RECIPROC motor continuous measuring (RCM), EndoPilot continuous measuring (ECM) and Raypex 6 manual measuring (RMM). When the measurement file reached the AC, the file was fixed in the tooth. The tooth was embedded in acrylic resin and the root tip was exposed, so that the histologic structure of the root canal and the file tip was visible for microscopic analysis. Afterwards, the distance of the file tip to the AC (DAC) was automatically computed with a specially developed software tool. RESULTS: The mean DAC were -13.18 µm (SD 88.46 µm) for RMM, -22.70 µm (SD 91.57 µm) for RCM and 18.74 µm (SD 88.11 µm) for ECM. The differences were not statistically significant (P = 0.181). The rates for instrumentation beyond the AC were not statistically different (Chi2 = 4.753, p = 0.096). CONCLUSIONS: All measurement methods showed a high accuracy in detecting the AC. The auto-stop function of these endodontic motors is a reliable addition to the endodontic armamentarium.

In Vitro Comparison of Raypex 6 and Endopilot Using a Novel, Computer-Aided Measurement System, for Determining the Working Length.

INTRODUCTION: Experimental evaluation of endometric devices usually relies on visual, subjective detection of the apical constriction to determine the accuracy of measurements. The aim of the present study was to analyze the accuracy of measurements of Raypex 6 and EndoPilot using a novel, objective image-analysis system. METHODS: Onehundred and twenty teeth were randomized and allocated to three groups: After coronal flaring, either Raypex 6 or EndoPilot were used to determine the endodontic working length during instrumentation using manual files (RPM and EPM group respectively). In addition, EndoPilot was used for continuous, automatic measurement during rotating instrumentation (EPA group). If the working length had been reached according to endometric results, the files were fixed in place. Tooth and file were then embedded and prepared for analysis. Subsequently, the distance between the tip of the file and the apical constriction (DAC) or the apical foramen (DAF) was calculated using trigonometric analysis and the position of the file relative to AC and AF was analyzed. RESULTS: Both inter- and intra-examiner-reliability of the trigonometric analysis were nearly perfect (ICC = 0.999, p<0.001). DAC was not significantly different between groups (p>0.05, t-test). DAF was significantly decreased when EPA had been used compared to EPM (p<0.05, Exact-test). EPA resulted in files being positioned beyond AF significantly more often than the other two methods (p<0.01). CONCLUSIONS: All methods allowed reliable detection of AC. However, EPA significantly increased the risk of overpreparation. Objective, digital assessment based on image analysis was suitable to compare the accuracy of different endometric devices.

Microbial community composition on modified dental implant surfaces: an in vivo study.

PURPOSE: The aim of the present in vivo study was to examine alterations of the microbial community structure in biofilms on different dental implant surfaces over the time. MATERIALS AND METHODS: Zirconium nitride-coated glass (ZrN-glass) and ZrN-coated polished titanium (ZrN-Ti) disks were used as substrates and polished titanium (Ti-pol) was used as a control. The specimens were mounted on removable intraoral splints in one adult. After 24 hours and 14 days of intraoral exposure, the microbial biofilms were analyzed by generating 16S rRNA gene clone libraries. RESULTS: ZrN coating of a Ti surface altered the microbial composition early on (24 hours), with a tendency to augment Lactobacillus-related phylotypes later. Long-term exposure (14 days) of dental implant surfaces to microbes resulted in a significantly different composition of the biofilm on all three tested surfaces. CONCLUSIONS: This preliminary study showed that a ZrN-Ti disk surface harbors a significantly different microbial composition from a polished Ti surface. Further improvement of ZrN physical vapor deposition coatings might help to influence the adhesion of bacteria that are less pathogenic, thereby reducing the risk of peri-implantitis.

Modified implant surfaces show different biofilm compositions under in vivo conditions.

OBJECTIVE: Plaque accumulation on implant surfaces can result in peri-implantitis with potential implant loss. The aim of the present study was to examine the influence of zirconium nitride (ZrN) as a potential implant surface on the biofilm composition and diversity in vivo. MATERIAL AND METHODS: ZrN- or titanium (Ti)-coated glass specimens and ZrN or roughened Ti discs were used as substrates. Pure glass and polished titanium served as controls. The specimens were mounted on removable intraoral splints in five adults. After 24 h of intraoral exposure, the biofilms were analyzed applying single-strand conformation polymorphism (SSCP analysis) of 16S rRNA genes. Sequence analysis of the dominant bands excised from the SSCP fingerprints allowed to taxonomically describe bacteria derived from biofilm samples. RESULTS: The highest number of bands was counted on pure glass and Ti 800. ZrN-coated glass and ZrN-coated titanium discs showed the lowest values for species richness. However, no significant differences were observed regarding the diversity of the identified bacterial species among all the surfaces examined. A total of 46 different bacteria were identified. The dominant bands within the fingerprints indicated bacteria belonging to the Streptococcus group as identified by their 16S rDNA sequence. CONCLUSION: A coating of glass surfaces with ZrN significantly reduced the species richness in early bacterial colonization but the diversity was not significantly changed. In consideration of the results obtained by this and former studies a ZrN coating appears to rather modify the quantity of early bacterial adherence than the quality of the microbial community structure.

Polymorphisms in the interleukin-1 (IL1) gene cluster are not associated with aggressive periodontitis in a large Caucasian population.

Polymorphisms in the interleukin-1 (IL1) gene have been suggested to influence transcription of IL1A (interleukin-1alpha) and IL1B (interleukin-1beta) and thereby the pathophysiology of periodontitis. This case-control association study on 415 northern European Caucasian patients with aggressive periodontitis (AgP) and 874 healthy controls was conducted to examine 10 single-nucleotide polymorphisms (SNPs) in the genes of the IL1 cluster for association with IL1A, IL1B, CKAP2L (cytoskeleton-associated protein 2-like), and IL1RN (IL-1 receptor antagonist). The results do not support an association between variants in the IL1 gene cluster and AgP. This case-control study had at least 95% power to detect genuine associations with variants carrying relative risks of at least 1.5 for heterozygous carriers and 2.25 for homozygous carriers. Previous reports of an association between IL1 promoter SNPs and periodontitis might reflect subpopulation effects and have to be interpreted with care.

Focal adhesion contact formation by fibroblasts cultured on surface-modified dental implants: an in vitro study.

A major consideration in designing dental implants is to create a surface that provides strong attachment of the implant to bone, connective tissue and epithelium. The aim of the present study was to examine the influence of different treatments of titanium (Ti) implant surfaces on focal adhesion contact (FAC) formation in fibroblast cultures. Human gingival fibroblasts were cultured on glass sheets and polished Ti discs with different surface coatings (applied by physical vapor deposition (PVD): Ti, titanium nitride (TiN), zirconium nitride (ZrN)) or on Ti discs with different surface topographies. For characterization of all surfaces, modified estimation of surface roughness and spacing parameter was carried out using a contact stylus profilometer. Contact angle measurements were carried out to calculate surface energy. Fibroblasts were prepared for transmission electron microscopy at day 3 after seeding, and the number of FACs and the ratio FAC/cellular cross-sections was determined at a length of 300 microm in ultrathin sections. To visualize the extracellular fibronectin and vitronectin molecules and the intracellular actin and vinculin in FAC areas, immunogold labeling was performed. The results revealed a strong correlation between the number of FACs and the surface roughness. The highest number of FACs and the majority of the immunogold-labeled intra- and extracellular matrix molecules were counted on surfaces with the lowest surface roughness: glass sheets coated with either Ti, TiN or ZrN (roughness average=0.03-0.1 microm). These surfaces appear to favor cellular attachment of human gingival fibroblasts and moreover in previous studies the hard coatings have been shown to reduce bacterial adhesion.

Prevalence of dental caries and periodontal disease in patients with inflammatory bowel disease: a case-control study.

AIM: Previous reports suggest a higher incidence of dental caries in patients with inflammatory bowel disease (IBD) and similarities in the immunopathogenesis of IBD and periodontitis. This study assessed the prevalence of periodontal disease and caries in patients with IBD. METHODS: In the present case-control study, 62 patients seeking treatment of IBD and 59 matched healthy controls of a dental practice were clinically examined. Oral soft-tissue alterations, the decayed, missing and filled tooth surface (DMF-S) index, dentine caries, plaque index (PI), bleeding on probing (BOP), probing pocket depth (PPD) and clinical attachment loss (CAL) were evaluated in each patient and in the controls. RESULTS: Patients with IBD showed a significantly higher number of oral manifestations compared with controls. The DMF-S index showed no significant differences, but there was a significantly higher number of subjects with dentine caries in patients with IBD. The mean PPD in patients with IBD was 2.08 versus 2.23 mm in controls (p=0.014). Compared with controls, patients with IBD had more sites with CAL of at least 4 mm (81% versus 64% in controls, p=0.07) and 5 mm (63% versus 46%, p=0.07), respectively. CONCLUSIONS: The results of this case-control study demonstrate a higher frequency of dentine caries in patients with IBD but the periodontal findings showed no distinct differences between cases and controls.