Root canal morphology of primary maxillary second molars:a micro-computed tomography analysis

Aim Successful endodontic treatment of primary teeth requires comprehensive knowledge and understanding of root canal morphology. The purpose of this study was to investigate the root canal configurations of primary maxillary second molars using micro-computed tomography. Methods Extracted human primary maxillary second molars (n = 57) were scanned using micro-computed tomography and reconstructed to produce three-dimensional models. Each root canal system was analysed qualitatively according to Vertucci's classification. Results 22.8% (n = 13) of the sample presented with the fusion of the disto-buccal and palatal roots; of these, Type V was the most prevalent classification. For teeth with three separate roots (n = 44), the most common root canal type was Type 1 for the palatal canal (100%) and disto-buccal canal (77.3%) and Type V for the mesio-buccal canal (36.4%). Overall, 7% (n = 4) of mesio-buccal canals were 'unclassifiable'. Conclusion The root canal systems of primary maxillary second molars were not only complex but had a range of configurations that may contribute to unfavourable clinical outcomes after endodontic treatment

In vitro comparative study on the mechanical behavior of Zirconia and Polyetheretherketone in applied dental sciences

OBJECTIVE: Recently, Zirconia and polyaryletherketone (PEEK) have attracted increasing interest as reliable and safe materials in dental applications, mainly because of their good biomechanical characteristics. The aim of this study was to investigate the response to different loads by prosthetic frameworks for supported fixed partial dentures (FPDs), thus simulating osseointegrated implants. MATERIALS AND METHODS: The specimens were divided into two groups (n= 5 each). Group A: FDPs in zirconia-ceramic; Group B: FDPs in PEEK-composite. These 2 groups were subjected to vertical loads so to evaluate structural deformation; then, they have been analyzed by scanning electron microscopy (SEM) at different magnifications. RESULTS: In tested samples, different types of mechanical failures have been observed. In Zirconia-specimens, chipping is the main failure noticed in this study, mostly in distal margins of the structure. Also, peek-specimens show failure and fracture. CONCLUSIONS: Zirconia and PEEK could be considered both good materials, but several investigations are needed to use these materials as an alternative to metals for fixed partial dentures

Evaluation of three instrumentation techniques at the precision of apical stop and apical sealing of obturation

OBJECTIVE: The aim of this study was to investigate the ability of two NiTi rotary apical preparation techniques used with an electronic apex locator-integrated endodontic motor and a manual technique to create an apical stop at a predetermined level (0.5 mm short of the apical foramen) in teeth with disrupted apical constriction, and to evaluate microleakage following obturation in such prepared teeth. MATERIAL AND METHODS: 85 intact human mandibular permanent incisors with single root canal were accessed and the apical constriction was disrupted using a #25 K-file. The teeth were embedded in alginate and instrumented to #40 using rotary Lightspeed or S-Apex techniques or stainless-steel K-files. Distance between the apical foramen and the created apical stop was measured to an accuracy of 0.01 mm. In another set of instrumented teeth, root canals were obturated using gutta-percha and sealer, and leakage was tested at 1 week and 3 months using a fluid filtration device. RESULTS: All techniques performed slightly short of the predetermined level. Closest preparation to the predetermined level was with the manual technique and the farthest was with S-Apex. A significant difference was found between the performances of these two techniques (

In vitro comparative study on the mechanical behavior of Zirconia and Polyetheretherketone in applied dental sciences

OBJECTIVE: Recently, Zirconia and polyaryletherketone (PEEK) have attracted increasing interest as reliable and safe materials in dental applications, mainly because of their good biomechanical characteristics. The aim of this study was to investigate the response to different loads by prosthetic frameworks for supported fixed partial dentures (FPDs), thus simulating osseointegrated implants. MATERIALS AND METHODS: The specimens were divided into two groups (n= 5 each). Group A: FDPs in zirconia-ceramic; Group B: FDPs in PEEK-composite. These 2 groups were subjected to vertical loads so to evaluate structural deformation; then, they have been analyzed by scanning electron microscopy (SEM) at different magnifications. RESULTS: In tested samples, different types of mechanical failures have been observed. In Zirconia-specimens, chipping is the main failure noticed in this study, mostly in distal margins of the structure. Also, peek-specimens show failure and fracture. CONCLUSIONS: Zirconia and PEEK could be considered both good materials, but several investigations are needed to use these materials as an alternative to metals for fixed partial dentures

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

Root Canal Anatomy of Maxillary and Mandibular Teeth

It is a common knowledge that a comprehensive understanding of the complexity of the internal anatomy of teeth is imperative to ensure successful root canal treatment. The significance of canal anatomy has been emphasized by studies demonstrating that variations in canal geometry before cleaning, shaping, and obturation procedures had a greater effect on the outcome than the techniques themselves. In recent years, significant technological advances for imaging teeth, such as CBCT and micro-CT, respectively, have been introduced. Their noninvasive nature allows to perform in vivo anatomical studies using large populations to address the influence of several variables such as ethnicity, aging, gender, and others, on the root canal anatomy, as well as to evaluate, quantitatively and/or qualitatively, specific and fine anatomical features of a tooth group. The purpose of this chapter is to summarize the morphological aspects of the root canal anatomy published in the literature of all groups of teeth and illustrate with three-dimensional images acquired from micro-CT technology.info:eu-repo/semantics/publishedVersio