Mechanisches Versagen thorakaler und lumbaler Wirbelkörper älterer Menschen - Vorhersage mittels Zwei-Energie Röntgenabsorptiometrie (DXA)

Osteoporotische Wirbelkörperfrakturen stellen ein großes sozioökonomisches Gesundheitsproblem dar. Klinisch wird derzeit zur Diagnosestellung der Osteoporose nach WHO-Empfehlung die lumbale DXA-Messung hinzugezogen. Die osteoporotischen Wirbelkörperfrakturen ereignen sich jedoch hauptsächlich in der thorakalen Wirbelsäule und im thorakolumbalen Übergangsbereich. Diese Areale sind jedoch der nicht-invasiven DXA-Messung aufgrund von Überlagerung anderer knöcherner Strukturen nicht zugänglich. In der vorliegenden Studie wurde die Hypothese untersucht, dass die auf der DXA basierende Vorhersage der Versagenslasten in der thorakalen Wirbelsäule durch a) die skelettale Heterogenität zwischen der lumbalen und thorakalen Wirbelsäule und b) durch die Artefakte bei der Bestimmung des lumbalen Knochenmineralgehaltes beeinflusst wird. Hierzu wurden die Korrelationen zwischen den in- und ex-situ erhobenen DXA-Parametern und den Versagenslasten bei älteren Individuen untersucht. Insgesamt wurden die Wirbelsäulen von 119 Präparate (76 Frauen, 82 ± 9 Jahre und 43 Männer, 77 ± 11 Jahre) untersucht. Nach der lumbalen DXA-Messung der Wirbelsäule unter In-situ Bedingungen in anterior-posteriorer (AP) Projektion erfolgte die Ex-situ – Messung in AP und in laterater Projektion. Anschließend wurden in einem axialen Kompressionsversuch, nach der Dreisegment-Methode, die Versagenslasten der Brustwirbelkörpersegmente (BWK) 5–7, 9–11 und dem Lendenwirbelkörpersegment (LWK) 2–4 bestimmt. Der Korrelationskoeffizient zwischen den Versagenslasten der beiden thorakalen Segmente betrug r = 0,85, die Versagenslasten der beiden thorakalen Segmente korrelierte mit dem lumbalen Segment nur moderat (BWK 6 vs. LWK 3 r = 0,61; BWK 10 vs. LWK 3 r = 0,68). Die laterale Ex-situ – DXA-Messung erbrachte signifikant höhere Korrelationen (p < 0,05) mit den Versagenslasten der lumbalen Wirbelsäule als die In-situ – DXA-Messung in AP-Projektion (r = 0,85 vs. 0,71). Die Korrelationen der thorakalen Versagenslasten mit der lateralen Ex-situ – DXA-Messung und der In-situ – DXA-Messung in AP-Projektion waren jedoch gleich (r = 0,69 vs. 0,67 für BWK 10 und r = 0,61 vs. 0,65 für BWK 6). Diese Ergebnisse demonstrieren eine substantielle Heterogenität der mechanischen Kompetenz innerhalb der Wirbelsäule älterer Individuen. Das mechanische Versagen der Lendenwirbelsäule kann am besten aus der lateralen DXA-Messung an explantierten Knochen vorhergesagt werden, somit scheint die lumbale In-situ – AP-Messung einer nicht unbedeutenden Beeinflussung durch die posterioren Element zu unterliegen, die die Vorhersagekraft der Messung reduzieren. Für die Vorhersage der Versagenslasten in der thorakalen Wirbelsäule und den thorakolumbalen Übergangsbereich ist die klinische In-situ – Messung der Lendenwirbelsäule in anterior-posteriorer Projektion der Ex-situ – Messung in beiden Projektionen jedoch nicht unterlegen. Somit scheint die lumbale In-situ – DXA in anterior-posteriorer Projektion ein mechanisch bedingtes Frakturrisiko für die thorakale und lumbale Wirbelsäule in gleicher Weise vorhersagen zu können. Die Artefaktbeeinflussung der lumbalen In-situ – AP-Messung scheint für die Vorhersage eines Frakturrisikos in der thorakalen Wirbelsäule eine eher untergeordnete Rolle zu spielen. Die klinische DXA-Messung der Lendenwirbelsäule in anterior-posteriorer Projektion kann daher als nicht-invasive Methode Aussagen über ein mögliches Frakturrisiko treffen und dazu beitragen Risikopatienten zu diagnostizieren und einer adäquaten, antiresorptiven Therapie zu unterziehen

Der Zahnstatus von Hochleistungssportlern:unter Berücksichtigung des erhöhten Energiebedarfs und der Ernährung

Die körperliche Unversehrtheit hat einen wichtigen Stellenwert für die Leistungsfähigkeit von Elite-Athleten, denen ein gesteigertes Gesundheitsbewusstsein nachgesagt wird. Die Zahngesundheit ist ein notwendiges Element. Karies wird seit jeher mit der Frequenz des Konsums zuckerhaltiger Speisen assoziiert. Sportler stellen wegen des erhöhten Energiebedarfs eine Risikogruppe dar. Die klinische Studie umfasste die klinische Untersuchung (DMF-S-Wert/FOTI) und die Erfassung des Kohlenhydratkonsums (Ernährungsfragebogen). Der Vergleich der Elite-Athleten (n=45) mit einer äquivalenten Gruppe (Zahnmedizinstudenten) gleichen Geschlechts, Alters und gleicher sozialer Herkunft aber ohne sportliche Aktivitäten zeigt einen signifikant besseren DMF-S-Wert der Sportler und andere Ernährungsgewohnheiten. Die Sportler konsumieren mehr Kohlenhydrate zu den Haupt- aber weniger zu Zwischenmahlzeiten. Reguläre Zahnpflege kombiniert mit Ernährungsberatungen macht sie weniger anfällig für Karies. The high performance standards required of elite athletes can only be attained by a totally healthy individual. Increased health awareness is assumed to sportsmen. Dental health is a necessary element. Since dental caries is associated with frequent use of sugar-containing products and since there is a potential risk for such consumption among sportsmen. We conducted a clinical study of a group of elite athletes (n =45) including DMFS (clinical examination assisted by FOTI) and carbohydrate intake frequency (standardized nutrition questionnaire). The control-group same age, sex and social background but not active in any sport was represented by dental students. The mean DMF-S-values were statistically significant lower (p < 0.001) in the athlete-group and the alimentary habits were different. Sportsmen consumed more carbohydrates in principal meals but less in-between meals. Regular dental care combined with nutritional consulting, make them less susceptible for dental decay

Shaping ability of BioRace, ProTaper NEXT and Genius nickel-titanium instruments in curved canals of mandibular molars: a MicroCT study

Aim To evaluate and compare the canal shaping ability of BioRace, ProTaper NEXT and Genius engine‐driven nickel‐titanium (NiTi) file systems in extracted mandibular first molars using micro‐computed tomography (MCT). Methodology Sixty mesial root canals of mandibular first molars were randomly divided into three equal groups, according to the instrument system used for root canal preparation (n = 20): BioRace (BR), ProTaper NEXT (PTN) or Genius (GN). Root canals were prepared to the full WL using a crown‐down technique up to size 35, .04 taper instruments for BR and GN groups and size 30, .07 taper instruments for the PTN group. MCT was used to scan the specimens before and after canal instrumentation. Changes in dentine volume, the percentage of uninstrumented canal surface and degree of canal transportation were evaluated in the coronal, middle and apical thirds of canals. Data were analysed statistically using one‐way analysis of variance and Tuckey's post hoc tests with the significance level set at 5%. Results There were no significant differences between the three groups in the terms of dentine removed after preparation and determination of the root canal volume, or percentage of uninstrumented canal surface (P > 0.05). No significant differences were found between the systems for canal transportation in any canal third (P > 0.05). Conclusions The shaping ability of the BR, PTN and GN NiTi file systems was equally effective. All instrumentation systems prepared curved root canal systems with no evidence of undesirable changes in 3D parameters or significant shaping errors

Multinational cross-sectional study and meta-analysis on radicular grooves, C-shaped canals, and taurodontism in mandibular first premolars across 20 countries

The success of root canal therapy is fully predicated upon a complete understanding of root and canal morphology and all the anatomical variations that can complicate the endodontic treatment. Of these morphological variations, taurodontism, RGs, and C-shaped canals are of note due to their implications on diagnosis, treatment planning, and endodontic success. This study aimed to investigate the prevalence and regional variations of C-shaped canals, RGs, and taurodontism across 20 countries using CBCT imaging and meta-analytic methods. A multicenter, cross-sectional study analyzed CBCT datasets from 6,000 participants (12,000 teeth) distributed equally across 20 countries. Standardized evaluation arrangements were utilized to identify RGs (RG), taurodontism, and C-shaped canals with their prevalence stratified by region, gender, and age. Statistical analyses cover subgroup comparisons, correlation studies, and sensitivity analysis using Cramer’s V. RGs had a pooled global prevalence of 20%, with high-rised rates in Africa. C-shaped canals reported a 10% global prevalence, mainly in Asia, On the Other hand taurodontism was lowest prevalent at 7%, with markable regional variability. Prominent bilateral symmetry was noticed for all features, and taurodontism showed the highest rate (98.33%). Important correlations existed among C-shaped canals, grooves, and taurodontism showing shared developmental pathways. The current study points out the significant prevalence, including anatomical variations of RGs, taurodontism, and C-shaped canals in mandibular 1st premolars, with substantial demographic and regional differences. The findings highlight the importance of perception of these features’ morphological interrelationships along with bilateral symmetry to increase diagnostic accuracy, clinical outcomes, and treatment planning

The effect of a manual instrumentation technique on five types of premolar root canal geometry assessed by microcomputed tomography and three-dimensional reconstruction

<p>Abstract</p> <p>Background</p> <p>Together with diagnosis and treatment planning, a good knowledge of the root canal system and its frequent variations is a necessity for successful root canal therapy. The selection of instrumentation techniques for variants in internal anatomy of teeth has significant effects on the shaping ability and cleaning effectiveness. The aim of this study was to reveal the differences made by including variations in the internal anatomy of premolars into the study protocol for investigation of a single instrumentation technique (hand ProTaper instruments) assessed by microcomputed tomography and three-dimensional reconstruction.</p> <p>Methods</p> <p>Five single-root premolars, whose root canal systems were classified into one of five types, were scanned with micro-CT before and after preparation with a hand ProTaper instrument. Instrumentation characteristics were measured quantitatively in 3-D using a customized application framework based on MeVisLab. Numeric values were obtained for canal surface area, volume, volume changes, percentage of untouched surface, dentin wall thickness, and the thickness of dentin removed. Preparation errors were also evaluated using a color-coded reconstruction.</p> <p>Results</p> <p>Canal volumes and surface areas were increased after instrumentation. Prepared canals of all five types were straightened, with transportation toward the inner aspects of S-shaped or multiple curves. However, a ledge was formed at the apical third curve of the type II canal system and a wide range in the percentage of unchanged canal surfaces (27.4-83.0%) was recorded. The dentin walls were more than 0.3 mm thick except in a 1 mm zone from the apical surface and the hazardous area of the type II canal system after preparation with an F3 instrument.</p> <p>Conclusions</p> <p>The 3-D color-coded images showed different morphological changes in the five types of root canal systems shaped with the same hand instrumentation technique. Premolars are among the most complex teeth for root canal treatment and instrumentation techniques for the root canal systems of premolars should be selected individually depending on the 3-D canal configuration of each tooth. Further study is needed to demonstrate the differences made by including variations in the internal anatomy of teeth into the study protocol of clinical RCT for identifying the best preparation technique.</p

Postoperative pain intensity after using different instrumentation techniques: a randomized clinical study

Postoperative pain is a frequent complication associated with root canal treatment, especially during apical instrumentation of tooth with preexisting periradicular inflammation OBJECTIVES: The aim of this clinical study was to evaluate the influence of the instrumentation techniques on the incidence and intensity of postoperative pain in single-visit root canal treatment. MATERIAL AND METHODS: Ninety patients with single root/canal and non-vital pulps were included. The patients were assigned into 3 groups according to root canal instrumentation technique used; modified step-back, reciprocal, and rotational techniques. Root canal treatment was carried out in a single visit and the severity of postoperative pain was assessed via 4-point pain intensity scale. All the participants were called through the phone at 12, 24 and 48 h to obtain the pain scores. Data were analyzed through the Kruskal–Wallis test. RESULTS: There was significant difference between all groups (p<0.05). The modified step-back technique produced postoperative pain significantly lower than the rotational (p=0.018) and reciprocal (p=0.020) techniques. No difference was found between the reciprocal and rotational techniques (p=0.868). Postoperative pain in the first 12 h period (p=0.763) and in the 24 h period (p=0.147) was not significantly different between the groups. However, the difference in the 48 h period was statistically different between the groups (p=0.040). CONCLUSION: All instrumentation techniques caused postoperative pain. The modified step-back technique produced less pain compared to the rotational and reciprocal techniques