DZZ International, 02/2019

Proven porcelain fused to metal restorations are increasingly being superceded by milled zirconia ones. Initially, in the 1960s the porcelain fused to metal crowns were quite resistant to abrasion which led to the "softer" opposing tooth showing significant signs of wear.

Introduction: The mechanical preparation of a root canal system is indispensable for a successful endodontic treatment outcome. Teeth with complex root canal morphologies, in particular, represent a special challenge; the practitioner should possess thorough knowledge of root canal morphology, as well as, be able to employ suitable endodontic instruments. The development of new nickel titanium alloys, through modifications made to their material properties, now permits the production of endodontic instruments which can meet even the highest requirements for root canal preparation. In this manner, the incidence of preparation errors and instrument fractures can be considerably decreased. Materials and Methods: A female patient with acute dental pain, originating from tooth 34, presented herself to the Department of Periodontology and Conservative Dentistry, a part of the University Clinic Münster. Following a detailed examination, root canal treatment on the tooth was performed. In this case report, R-Pilot and Reciproc Blue instruments (both VDW, Munich, Germany) were employed to treat a first mandibular premolar with a Vertucci type III canal configuration. Results: In the present case, in spite of complex root canal morphology, a sufficient and satisfactory root canal treatment outcome was achieved. This was realized through the use of R-Pilot files to establish an initial glide path and the subsequent use of Reciproc Blue files for further canal preparation. Conclusion: Knowledge of possible root canal system configurations and identification of such cases in daily clinical practice is a prerequisite for successful root canal therapy. Furthermore, a case-specific selection of endodontic instruments should be performed in order to prevent preparation errors and instrument fractures. It is also important to point out that a preceding glide path preparation helps to facilitate an easier and safer canal preparation and should therefore be considered as obligatory. Keywords: Blue-Wire, M-Wire, R-Pilot, Reciproc-Blue, glide path

Introduction: In the 1990s computerized tooth colour measuring instruments were introduced on to the dental market that facilitated the practical recording of tooth shades in everyday practice. This experimental study evaluated two such devices; comparing the reproducibility, reliability and interreliability of the dental spectrophotometer QuattroShade (QS, Goldquadrat GmbH, Hannover, Germany) and the VITA Easyshade Advance 4.0 (VES, Vita Zahnfabrik, Bad Säckingen, Germany). Material and Method: Under simulated clinical conditions the tooth colours and L*a*b* data were measured for 2 extracted human teeth (tooth 12 and tooth 21) in three experimental phases. (I) 3 series of measurements were taken using both devices on both teeth. Initially, calibration took place after every measurement, then in the two following series at intervals after every five and ten measurements respectively (n = 250). (II) 51 recruits each made three measurements (n = 153) for tooth 21 using both devices. Equipment was calibrated before each new user. (III) tooth 21 was measured 153 times (n = 153) with calibration after every third reading. The statistical program SPSS (Inc., U.S.A for windows version 24.0) was used to analyse the data. Results: Significant differences (Wilcoxon-test, Friedman-test, p ≤ 0.05) were found between the reproducibility measurements of each device. A comparison of measurements between the devices also showed differences. A correlation between frequent and longer calibration intervals was evident. Less deviation occurred with fewer calibrations (after every ten measurements) than with more frequent calibrations (after each measurement). The reproducibility of the L*a*b* values was higher using the VES when compared to the QS. Concerning reliability, slight differences in delta (Δ) E values were noted for both devices. The QS showed better values between multiple users than the VES. All deviations are not relevant for clinical purposes (ΔE = 0.8–2.2). Conclusion: This study has shown that both devices for tooth colour determination are suitable for daily practice. However, a visual check should still be made with a conventional colour scale. Keywords: digital tooth colour determination, reliability, reproducibility, spectrophotometer

Introduction: An efficient removal of biofilm plays a major role in the prevention of caries as well as gingivitis and periodontitis. In this respect, besides the professional hygiene measures performed in the dental practice, an effective, self-responsible, home-based oral hygiene should also take place. A predilection site for caries and gingivitis is represented by the tooth surfaces below the proximal contact points, which can hardly be cleaned with toothbrushes alone. The aim of the present cross-over pilot study was to investigate whether two-times brushing in accordance with the CIOTIPlus-System (Chewing, Inside, Outside, Tongue and Interdental area, Plus: second brushing) using different brushing regimens (time and type of interdental hygiene tools) has an effect on interdental cleaning (IDC). Methods: 15 subjects (7 females, 8 males, mean age 50.1 ± 6.5 years) were included in this study with a split-mouth design. On five appointments, each of which was preceded by a 72-hour plaque accumulation phase, ten brushing regimens were evaluated on their ability to clean the approximal surfaces; these regimens employed the use of a standard manual toothbrush and interdental hygiene tools. Six brushing regimens using the sequence "brushing – IDC- brushing" (flossing vs. flossing interdental brushing vs. interdental brushing vs. soft picks vs. interdental brushing from vestibular and oral with or without gel) and four brushing regimens using the sequence "IDC – brushing – brushing" (flossing vs. interdental brushing vs. flossing interdental brushing vs. soft picks) were tested. The participants were instructed to brush their teeth according to the "CIOTIPlus"-System. The Quigley-Hein Index (QHI) and the modified Approximal Plaque Index (QH-API) were determined at three time points in order to assess plaque reduction: before brushing (t0), after the first brushing and IDC (t1) as well as after the second brushing (t2). Results: At t1, a significant reduction of the QHI and QH-API values was observed in all groups compared to t0. The highest reduction of the QH-API was observed in the group "brushing – interdental brushing from vestibular and oral – brushing" (BI2B) (ΔQH-API-t0-t1: 2.44 ± 0.45). At t2, the QHI and QH-API values were further significantly reduced in all groups. The greatest reduction of the QH-API was once again observed in the group BI2B (ΔQH-API-t0-t2: 3.16 ± 0.41). However, after the second brushing, the group differences were very small (except for BI2B). Conclusion: Interdental brushing from vestibular and oral seems to be the most effective IDC regimen for reducing the approximal plaque values. Second brushing, as part of the "CIOTIPlus"-System, leads to a higher plaque reduction on smooth and approximal surfaces compared to the one-time brushing, no matter what kind of interdental hygiene tools/ brushing regimens are used. Therefore, any cleaning performance deficits associated with the use of different hygiene tools in the approximal surfaces could be compensated using this approach. Keywords: CIOTIPlus-System, interdental cleaning, plaque reduction, second brushing