Orthodontic System Modeled and Simulated with the Lingual Technique to Assess Tooth Forces.

CBCT (cone beam computed tomography) is an imaging investigation that provides three-dimensional (3D) images of craniofacial structures. The purpose of this study is to determine the mechanical behavior of an orthodontic system where the lingual treatment technique was used in a 25-year-old female patient from whom a set of CBCT scans was used. CBCT images were processed through software programs such as Invesalius, Geomagic, and Solid Works, to create models containing virtual solids. These models were then imported into Ansys Workbench 2019 R3 (a finite element method software program) for successive simulations to generate displacement maps, deformations, stress distributions, and diagrams. We observed that in the lingual technique, the lowest force occurring on the maxillary teeth is at 1.1, while the highest force appears at 2.3. In the mandible, the lowest force occurs at 4.6, and the highest force at 3.1. The values of the forces and the results of the finite element method can represent a basis for the innovation of new orthodontic springs and also of bracket elements. Thus, by using new technologies, orthodontic practice can be significantly improved for the benefit of patients. Other virtual methods and techniques can be used in future studies, including the application of virtual reality for orthodontic diagnosis.

An atypical anatomy of permanent mandibular second molar with five roots.

Especially in molars that may have sometimes aberrant additional root canals, the complexity of tooth internal morphology in individual cases sometimes does not match to admitted classification rules and underlines the risk of missed anatomy during the endodontic management. To our knowledge, a permanent mandibular second molar with independent five roots, three mesial and two distal, each of them harboring a single canal, was not yet reported. Despite the treatment difficulties this tooth could be successfully approached by using dental operative microscope and cone-beam computed tomography (CBCT) with small field of view. Though CBCT is not a routine imagistic examination, in case of atypical tooth anatomy aiming to establish adequate diagnosis and treatment plan, the successful clinical outcome prevails over the irradiation dose.

Attitudes towards COVID­19 vaccination in patients with cancer: A cross­sectional study of 12 oncology centers.

Patients with cancer are a high-priority population for COVID-19 vaccination, as per guideline recommendations. The present cross-sectional study was performed to assess the perception of patients with cancer from Romania regarding COVID-19 vaccines. The study included 932 patients with solid and hematologic malignancies. This was a multicenter study including 12 oncology centers located in Western and Northwestern Romania. Between December 2021 and January 2022, patients with cancer completed an individual paper questionnaire regarding acceptance of the SARS-CoV-2 vaccination, type of vaccine, side effects and source of information. During the first year of the vaccination campaign in Romania, 58.05% (541/932) of the investigated patients received COVID-19 vaccines. The vaccination rate was highest in the 61-70 year age group (61.22%). The most frequently used vaccine was Pfizer-BioNTech (72%). There was a statistically significant association between the rate of vaccination and the area of residence and level of education (P<0.001), with rural residence and a lower level of education being predictive factors for COVID-19 vaccination hesitancy. Patients living in rural areas used non-medical sources (e.g. mass media, social platforms) as their main source of information (53.40%, 204/382), whereas patients living in urban areas (64.90%, 357/550) used predominantly medical sources (e.g. recommendations from oncologists and general practitioners). The main source of information among non-vaccinated patients was mass media (e.g. television, radio); 72.38% vs. 29.67% among vaccinated patients. For the latter, the primary source of information was the recommendations made by oncologists (59.70%) and general practitioners (56.76%). The most commonly reported side effect was injection site pain (20-33% for the first dose and 5-27% for the second dose). In conclusion, the present study confirmed that patients with cancer may be reluctant to receive a COVID-19 vaccine, mainly due to the fear of its potential side effects. Although there is scientific evidence to support the efficacy and safety of vaccines, the primary source of information for patients may affect vaccine uptake, thus affecting the efforts to stop the pandemic. Furthermore, the present study revealed that non-vaccinated patients preferred mass media as their main source of information, whereas vaccinated patients relied on the recommendations made by oncologists or general practitioners.

Incidence of the middle mesial canals in mandibular permanent molars in a Romanian population by cone-beam computed tomography.

INTRODUCTION: Untreated middle mesial canals (MMCs) of mandibular permanent molars can result in endodontic treatment failure. AIM: The aim of this retrospective study was to investigate the incidence of MMC of mandibular molars in a Romanian population. PATIENTS, MATERIALS AND METHODS: In total, there were evaluated 144 mandibular first permanent molars and 140 mandibular second permanent molars by using cone-beam computed tomography (CBCT) scans. RESULTS: The MMC was identified in 5.67% of mandibular first permanent molars, respectively in 4.28% of mandibular second permanent molars. The male∕female ratio of MMC presence was 1:3 of mandibular first molars and inverted for mandibular second molars (5:1). The presence of MMC in mandibular first molars was associated in all cases of our study with a second distal canal, unlike the mandibular second molars where no second distal canal was associated with a MMC. CONCLUSIONS: In Romanian population, the MMC of mandibular first molars, when present, is commonly associated with a second distal canal, unlike the mandibular second molars where the occurrence of a MMC was associated with only one distal canal. When performing the preoperative evaluation, it has also to be considered the patient gender, since the male∕female ratio of MMC was 1:3 in mandibular first molars and 5:1 in mandibular second molars.

A rare case diagnosed as dentin dysplasia type II.

According to their phenotypic features, the hereditary dentin defects in humans are categorized in two major classes: dentinogenesis imperfecta and dentin dysplasia. At its turn, the dentin dysplasia is subdivided in dentin dysplasia type I and dentin dysplasia type II, a milder clinical manifestation of the condition. Here we report the clinical and radiographic findings of dentin dysplasia type II in two members of a family, a young adult female and her mother. Except a mild shade change of the incisal margins in upper central incisors and left upper canine of the daughter no abnormal occlusal wear or crown shape change of the teeth were disclosed in both patients. However, confluent large pulp stones in the thistle-tube shaped pulp chambers and pulpal obliteration were a common finding. The condition was diagnosed as dentin dysplasia type II.

Middle mesial canal of the permanent mandibular first molars: an anatomical challenge directly related to the outcome of endodontic treatment.

To effectively clean and shape the mandibular permanent first molars it is mandatory to understand in detail their complex internal anatomy. The middle mesial canal is an additional canal located between the usual mesiobuccal and mesiolingual canals in the mesial root of mandibular first molars. The incidence of the middle mesial canal, its relationship with main canals of the mesial root and the possibility for it to be negotiated is an important practical issue in endodontics. To identify the presence of this canal is mandatory. Accordingly, a modified endodontic access, the use of the operating microscope and periapical radiographs in two different horizontal projections are indicated to enhance the long-term favorable outcome of the endodontic treatment.

Occurrence of invasive cervical resorption after the completion of orthodontic treatment.

The invasive cervical resorption (ICR) is an irreversible and progressive loss of tooth hard tissues involving coronal and root dentine that usually affects single permanent teeth. The aim of this study was to present the pattern of ICR lesions detected in three patients with no contributory medical and dental anamnesis, at different time periods after orthodontic tooth movements. Conventional radiographs and cone-beam computed tomography (CBCT) images were obtained by X-Mind™ (Satelec), respective 3D Accuitomo (Morita). The present clinical study confirmed that orthodontic forces might be a key factor for generating an ICR and the risk of lesion occurrence is increased in long movements of the teeth because the orthodontic forces act continuously an extended time. However, it should not be overlooked the synergistic effect of additional factors such as traumatic injuries, periodontal inflammation, clenching, and grinding. The more advanced ICR lesions found in our study, described as Heithersay Class 3 and Class 4, appeared on conventional radiographs as irregular, diffuse, mottled radiolucencies extended both to the crown and deeply into the tooth root. CBCT proved to have a superior accuracy in detection and assessing the severity of ICR, since the conventional intraoral radiographs cannot afford an early and proper identification of the resorptive defect. Moreover, the CBCT image allows an accurate inspection of all surfaces of tooth due to the slices in sagittal, axial and coronal planes, and to avoid erroneous diagnostic conclusions. Currently, due to CBCT scan, the nature and extension of ICR lesion into the tooth structures can be exactly evaluated.

Associated lesions of peri-implant mucosa in immediate versus delayed loading of dental implants.

Currently, immediate loading of dental implants is very attractive as a standard protocol for prosthetic restorations in edentulous patients. The aim of this study is to find out the intimate peri-implant mucosa response depending on timing of implant loading, immediate or delayed. Fifty-one screw implants Alpha Bio (Alpha-Bio Tec, Israel) were inserted in 42 partially edentulous patients according to standardized surgical techniques. At six months of loading, samples of peri-implant mucosa were harvested from 27 immediate loaded, respectively 24 delayed loaded implants, and subjected to microscopic examination. Peri-implant mucosa in both loadings revealed a continuous and stable stratified squamous epithelium with moderate acanthosis and slight hyperkeratosis. Severe fibrosis and tendency to scar-like lesions were present mainly in immediate loading. Slight to moderate density of inflammatory chronic cell populations of non-uniform feature was common to both loading protocols. As compared to lymphocytes, higher scores of plasma cells were encountered in immediate loading. In immediate and delayed loading, the peri-implant mucosa as a new generated structure does not reveal different tissue responses. After six month of prosthetic loading, the healthy peri-implant mucosa is compatible with fibrosis and minor chronic inflammatory reactions.

The use of cone beam computed tomography in the diagnosis and management of internal root resorption associated with chronic apical periodontitis: a case report.

Internal root resorption is a consequence of chronic pulp inflammation. Later on, the pulp necrosis followed by a chronic apical periodontitis is installed. Hence, usually, in clinical practice, both lesions have to be simultaneously managed. Conventional periapical radiograph is mandatory in diagnosis. Improving the diagnosis and management of both lesions, cone beam computed tomography proves to be more reliable than conventional radiography.

Rare multiple internal root resorption associated with perforation - a case report.

Multiple internal root resorption is a rare outcome of chronic irreversible pulpitis. In some cases, a chronic apical periodontitis can be later on associated. Usually, the conventional intraoral radiograph is mandatory in diagnosis but only CBCT proved to detect the true location, shape and size of resorptive defect and, if present, a perforation generated by resorption extension through the canal wall. Unlike the intraoral radiograph, CBCT is also able to improve the management and the recall evaluation, demonstrating a higher accuracy and reliability.

Validating cone-beam computed tomography for peri-implant bone morphometric analysis.

Cone-beam computed tomography (CBCT) has been recently used to analyse trabecular bone structure around dental implants. To validate the use of CBCT for three-dimensional (3D) peri-implant trabecular bone morphometry by comparing it to two-dimensional (2D) histology, 36 alveolar bone samples (with implants n=27 vs. without implants n=9) from six mongrel dogs, were scanned ex vivo using a high-resolution (80 µm) CBCT. After scanning, all samples were decalcified and then sectioned into thin histological sections (∼6 µm) to obtain high contrast 2D images. By using CTAn imaging software, bone morphometric parameters including trabecular number (Tb.N), thickness (Tb.Th), separation (Tb.Sp) and bone volume fraction (BV/TV) were examined on both CBCT and corresponding histological images. Higher Tb.Th and Tb.Sp, lower BV/TV and Tb.N were found on CBCT images (P<0.001). Both measurements on the peri-implant trabecular bone structure showed moderate to high correlation (r=0.65-0.85). The Bland-Altman plots showed strongest agreement for Tb.Th followed by Tb.Sp, Tb.N and BV/TV, regardless of the presence of implants. The current findings support the assumption that peri-implant trabecular bone structures based on high-resolution CBCT measurements are representative for the underlying histological bone characteristics, indicating a potential clinical diagnostic use of CBCT-based peri-implant bone morphometric characterisation.