Search results for "dentistry"

Bolton ratios in Portuguese subjects among different malocclusion groups

2018

Background Several methods have been described to estimate inter-arch tooth size relationship, such as Bolton's ratios. The aims of this study were to verify the validity of Bolton indexes in a sample of untreated Portuguese subjects based on Angle classification and to evaluate the gender difference. Material and Methods 168 pre-treatment dental casts of orthodontics Portuguese subjects (59 males and 109 females) with different occlusions were used, which were selected randomly from 541 consecutively treated orthodontic patients. The mesiodistal widths from first molar to first molar were measured on each pre-treatment cast to the nearest 0.01 mm using digital caliper, and Bolton's anterio…

Expansion of permanent first molars with rapid maxillary expansion appliance anchored on primary second molars

2018

Background To evaluate how the amount of expansion of the primary second molars, the patient's age, and the skeletal maturation stage influence the amount of expansion at the level of the permanent first molars. Material and methods Fifty-five patients aged between 6 and 11 years with a cervical vertebral maturation stage of CS1 or CS2 were retrospectively selected. The intermolar width was measured before and after expansion to evaluate the amount of expansion achieved at the level of the primary second molars and the permanent first molars. Stepwise multiple linear regression was used to evaluate how the amount of primary molars expansion, the patient's age, and the cervical vertebral mat…

2020

Orthodontic tooth movement to therapeutically align malpositioned teeth is supposed to impact blood flow in the surrounding tissues. Here, we evaluated actual vascularization in the tension area of the periodontal ligament during experimental tooth movement in rats (N = 8) with magnetic resonance imaging (MRI). We inserted an elastic band between the left upper first and the second rat molar; the right side was not treated and served as control. After four days of tooth movement, we recorded T1-weighted morphologic and dynamic-contrast-enhanced MRI sequences with an animal-specific 7 Tesla MRI to assess of local vascularization. Furthermore, we quantified osteoclasts and monocytes in the pe…

The effect of pre-cure bracket movement on shear bond strength during placement of orthodontic brackets, an in vitro study

2017

Background The purpose of this study was to determine the influence of linear and rotational pre-cure bracket displacement during the bonding procedure on shear bond strength (SBS) of orthodontic brackets. Material and Methods Stainless steel orthodontic premolar brackets were bonded to the buccal surfaces of 50 human pre-molars with a conventional two-step bonding protocol. Extracted human pre-molars were divided into 5 groups (n=10/group). In the Control Group, the brackets were bonded with no pre-cure bracket displacement or rotation. The Rotation Group was bonded with 45 degrees of pre-cure rotation. The Displacement Group was bonded with 2mm pre-cure linear displacement. The Rotation-D…

Transportation Assessment in Simulated Curved Canals after preparation with Twisted File Adaptive and BT-Race instruments.

2017

BACKGROUND This study compared the incidence of deviation along curved canals after preparation with two nickel-titanium (NiTi) rotary systems, Twisted File Adaptive and BT-RaCe. MATERIAL AND METHODS Forty resin training blocks with curved canals were filled with ink and divided into two groups according to the instrumentation technique. Preinstrumentation images were acquired by using a stereomicroscope. The canals were up to an instrument #35/0.04. Postinstrumentation images were captured using the same conditions, and the images were superimposed. The amount of resin removed was measured at 8 different points, beginning at the apical terminus of the canal. Differences in the mesial and d…

Elongated styloid process: An epidemiological study on digital panoramic radiographs

2017

Background The styloid process is a projecton of the temporal bone, its lenght is between 20 to 30 mm, when it is longer than 30 mm it is defined elongated styloid process. The aim of this study is an epidemiological evaluation of 1003 digital panoramic radiographs in an Italian population between 5 and 90 years old. Material and methods This is a retrospective analysis and the radiographs were selected from the Complex Operating Unit of Dentistry of Padua University Hospital database. The radiographs were performed using a Sirona Ortophos XG and the styloid process length was measured using the measuring tool of Sidexis Software. It was measured from the point where it left the temporal bo…

Osteoradionecrosis of the jaws triggered by dental implant placement: a case report

2019

Background The decision-making process about how to rehabilitate edentulous osseous defects in patients with head and neck cancer history can be complex. Even though, endosseous dental implants could be considered to be the first choice for treating these patients, it is highly important to be aware of the complications that might occur. The aim of this report was to describe the clinical features of mandibular fracture after dental implants placement on a cancer irradiated patient and update the available information about this event. Case report The case describes a 70-year-old man, with medical background of radiotherapy in jaw bones to treat a carcinoma in the floor of the mouth and lat…

Apoptosis and apoptotic pathway in actinic prurigo by immunohistochemistry

2015

Background Actinic prurigo (AP) is an idiopathic photodermatosis, this entity requires exposure to UV-B and -A to develop lesions. Apoptosis is a physiological death program that can be initiated by a permanently active mechanism (extrinsic pathway) or irreparable damage (intrinsic pathway). Material and Methods Descriptive study, the sample size comprised 64 paraffin blocks of tissue with a diagnosis of AP. In H&E-stained slides, the diagnosis of AP was corroborated, and 1-µm-thick sections were processed for immunohistochemistry (IHC). A database was constructed with SPSS version 20, Inc., Chicago, IL, USA, and descriptive statistics were analyzed by X2 test and comparison of means. Resul…

Prognostic value of matrix metalloproteinase-9 expression in oral squamous cell carcinoma and its association with angiogenesis

2016

Background: Breakdown of extracellular matrix (ECM) is one of the important hallmarks of cancer progression which facilitates the invasion of tumoral cells to the surrounding tissue. Matrix metalloproteinases (MMPs) can degrade various components of the ECM and basement membrane. The aim of this study was to determine the role of matrix metalloproteinases-9 protein in the biologic behavior of oral squamous cell carcinoma (OSCC) and its relation with tumor angiogenesis. Material and Methods: In this study 42 OSCC and 15 normal epithelium were reviewed by immunohistochemical staining for matrix metalloproteinases-9 and CD105. Results: Matrix metalloproteinases-9 expression was detected in 32 …

Detection of human papillomavirus DNA in formalin-fixed, paraffin-embedded squamous papillomas of the oral cavity

2018

Background Squamous papillomas are exophytic proliferations of surface oral epithelium. Human papillomavirus (HPV) infection is widely accepted as the etiology of squamous papillomas however the virus cannot be detected in a significant percentage of lesions. Material and methods Using polymerase chain reaction (PCR), we tested 35 formalin-fixed paraffin-embedded (FFPE) squamous papillomas for the presence of HPV DNA. Results Six papillomas (17%) tested positive for HPV DNA; four contained HPV-6 and two contained HPV-11. Given that β-globin DNA was only identified in half of the samples, DNA degradation appears to have significantly impacted the results. Conclusions The results likely repre…