Search results for "Teeth"
showing 10 items of 229 documents
A study on stress distribution to cement layer and root dentin for post and cores made of CAD/CAM materials with different elasticity modulus in the …
2019
Background To evaluate the stress distribution in a maxillary central incisor with different post and cores made of six CAD/CAM materials with different elastic modulus in the absence of ferrule using the finite element analysis. Material and methods A three-dimensional endodontically treated maxillary central incisor restored with an all-ceramic crown was modelled in Rhinoceros (5.0 SR8, McNeel). The geometries were analyzed in ANSYS 17.2 (ANSYS Inc.) considering isotropic, homogeneous, linearly elastic materials with perfectly bonded contacts. The elastic moduli (E) of the post-and-cores defined the groups to be compared: nanoceramic resin (E=12.8GPa); composite resin (E=16GPa); hybrid ce…
Decreased dentin tubules density and reduced thickness of peritubular dentin in hyperbilirubinemia-related green teeth.
2016
BACKGROUND It is stated anecdotally that patients with liver diseases in childhood who develop green teeth have increased risk for rampant caries, which may be secondary to changes in dental structure. The aim of this study was to test the hypothesis that hyperbilirubinemia affects the dentin morphology of green teeth. MATERIAL AND METHODS Sixteen primary teeth were prepared and divided into two groups (green teeth, n = 8 and control, n = 8), which were transversely fractured across the cervical third of the dental crowns; dentin was prepared and sputter-coated with gold, and examined under a scanning electron microscope. The mean density and mean diameter of dentin tubules, as well as the …
Tooth oxygen isotopes reveal Late Bronze Age origin of Mediterranean fish aquaculture and trade
2018
AbstractPast fish provenance, exploitation and trade patterns were studied by analyzing phosphate oxygen isotope compositions (δ18OPO4) of gilthead seabream (Sparus aurata) tooth enameloid from archaeological sites across the southern Levant, spanning the entire Holocene. We report the earliest evidence for extensive fish exploitation from the hypersaline Bardawil lagoon on Egypt’s northern Sinai coast, as indicated by distinctively high δ18OPO4 values, which became abundant in the southern Levant, both along the coast and further inland, at least from the Late Bronze Age (3,550–3,200 BP). A period of global, postglacial sea-level stabilization triggered the formation of the Bardawil lagoon…
Automated segmentation and description of the internal morphology of human permanent teeth by means of micro-CT
2020
High-resolution micro-computed tomography is a powerful tool to analyze and visualize the internal morphology of human permanent teeth. It is increasingly used for investigation of epidemiological questions to provide the dentist with the necessary information required for successful endodontic treatment. The aim of the present paper was to propose an image processing method to automate parts of the work needed to fully describe the internal morphology of human permanent teeth. One hundred and four human teeth were scanned on a high-resolution micro-CT scanner using an automatic specimen changer. Python code in a Jupyter notebook was used to verify and process the scans, prepare the dataset…
Clinician-related factors behind the decision to extract an asymptomatic lower third molar. A cross-sectional study based on Spanish and Portuguese d…
2017
Background: Scientific literature estimates that around 18 to 40 % of asymptomatic third molars are extracted. The aims of the present study were to determine the indications for extraction of asymptomatic lower third molars in a sample of Spanish and Portuguese dentists, and to relate these indications to the clinicians’ training and professional experience. Material and Methods: A survey consisting of 15 cases of asymptomatic lower third molars was emailed to Portuguese and Spanish dentists. The clinicians were asked to assess the level of difficulty of the extractions and to make a reasoned recommendation based on the panoramic radiographs, gender and age of the patients. Results: 381 cl…
Sharp mandibular bone irregularities after lower third molar extraction: incidence, clinical features and risk factors
2012
Objectives: The purpose of this study was to determine the incidence and clinical symptoms associated with sharp mandibular bone irregularities (SMBI) after lower third molar extraction and to identify possible risk factors for this complication. Study Design: A mixed study design was used. A retrospective cohort study of 1432 lower third molar extractions was done to determine the incidence of SMBI and a retrospective case-control study was done to determine potential demographic and etiologic factors by comparing those patients with postoperative SMBI with controls. Results: Twelve SMBI were found (0.84%). Age was the most important risk factor for this complication. The operated side and…
Quality of life after upper third molar removal: a prospective longitudinal study
2017
Background Third molar extraction is a very common procedure in Dentistry. The aim of this study was to evaluate the quality of life (QoL) and satisfaction of patients undergoing extraction of an upper third molar under local anesthesia. A second objective was to describe the evolution of self-reported pain measured in a visual analogue scale (VAS) in the 7 days after surgery and its relationship with pre- and intraoperative factors. Material and Methods A prospective longitudinal cohort study was made. Fifty-five patients received a questionnaire assessing social and working isolation, eating and speaking ability, diet modifications, sleep impairment, physical appearance, discomfort at sut…
The prevalence of root dilacerations in a Turkish population
2009
Objectives: The aim of this study was to determine the prevalence of root dilaceration in a Turkish dental patient population with respect to sexes and dental localization in relation between sex and this anomaly. Study Design: A retrospective study was performed using periapical radiography of 2,124 patients ranging in age from 15 to 65. All data (age, sex and systemic disease or syndrome) was obtained from the files. These patients were analyzed for root dilaceration. Descriptive characteristics of sexes, jaws, and dental localization were recorded. The Pearson chi-squared test was used. Results: Of 2,251 patients, 214 (9.5%) had root dilaceration. Root dilacerations were determined in 27…
Predictive factors of difficulty in lower third molar extraction : a prospective cohort study
2017
Background Several publications have measured the difficulty of third molar removal, trying to establish the main risk factors, however several important preoperative and intraoperative variables are overlooked. Material and Methods A prospective cohort study comprising a total of 130 consecutive lower third molar extractions was performed. The outcome variables used to measure the difficulty of the extraction were operation time and a 100mm visual analogue scale filled by the surgeon at the end of the surgical procedure. The predictors were divided into 4 different groups (demographic, anatomic, radiographic and operative variables). A descriptive, bivariate and multivariate analysis of th…
Coronectomy - An alternative approach to remove impacted teeth in oncological patients.
2018
Background Coronectomy involves the section of the tooth crown leaving the roots in the socket. Possibility of inferior alveolar nerve injury and mandibular fracture are the main indications for this approach. Herein, we describe a case series of coronectomy to highlight its indication in normal and oncological patients. Material and methods A total of 9 patients were submitted to coronectomy, 6 of them were oncological. Three patients were evaluated before head and neck radiotherapy (HNRT), 2 after HNRT and 1 before bone marrow transplantation. Results Mean age of the patients was 49 years, most of them male (n=7). Lower third molars were the main teeth that received this procedure, and al…