FEM and Von Mises analysis on prosthetic crowns structural elements: evaluation of different applied materials

The aim of this paper is to underline the mechanical properties of dental single crown prosthodontics materials in order to differentiate the possibility of using each material for typical clinical condition and masticatory load. Objective of the investigation is to highlight the stress distribution over different common dental crowns by using computer-aided design software and a three-dimensional virtual model. By using engineering systems of analyses like FEM and Von Mises investigations it has been highlighted the strength over simulated lower first premolar crowns made by chrome cobalt alloy, golden alloy, dental resin, and zirconia. The prosthodontics crown models have been created and put on simulated chewing stresses. The three-dimensional models were subjected to axial and oblique forces and both guaranteed expected results over simulated masticatory cycle. Dental resin presented the low value of fracture while high values have been recorded for the metal alloy and zirconia. Clinicians should choose the better prosthetic solution for the teeth they want to restore and replace. Both prosthetic dental crowns offer long-term success if applied following the manufacture guide limitations and suggestions

FEM and Von Mises Analysis on Prosthetic Crowns Structural Elements: Evaluation of Different Applied Materials

The aim of this paper is to underline the mechanical properties of dental single crown prosthodontics materials in order to differentiate the possibility of using each material for typical clinical condition and masticatory load. Objective of the investigation is to highlight the stress distribution over different common dental crowns by using computer-aided design software and a three-dimensional virtual model. By using engineering systems of analyses like FEM and Von Mises investigations it has been highlighted the strength over simulated lower first premolar crowns made by chrome cobalt alloy, golden alloy, dental resin, and zirconia. The prosthodontics crown models have been created and put on simulated chewing stresses. The three-dimensional models were subjected to axial and oblique forces and both guaranteed expected results over simulated masticatory cycle. Dental resin presented the low value of fracture while high values have been recorded for the metal alloy and zirconia. Clinicians should choose the better prosthetic solution for the teeth they want to restore and replace. Both prosthetic dental crowns offer long-term success if applied following the manufacture guide limitations and suggestions

Interface Between MTA and Dental Bonding Agents: Scanning Electron Microscope Evaluation

Nowadays, the material that offers the best sealing characteristic in the field of endodontic treatment is the mineral trioxide aggregate (MTA), nevertheless, this material necessities an adhesive bonding agent to perfectly join to the dental surface. The aim of this study was to analyze using a scanning electron microscope (SEM) the possible microgap between the adhesive, MTA, and the dental surface

Tissue fluorescence imaging (VELscope) for quick non-invasive diagnosis in oral pathology

Oral squamous cell carcinoma is the most common form of malignancy of the oral cavity; its incidence is increasing and latestage presentation is common. It is usually predated by oral premalignant disorders. For this reason, early diagnosis is fundamental to reduce the malignant transformation of oral premalignant disorders and for increase the survival rate for oral cancer. Scraping the surface of the lesion is useful for having cytological features of the investigated tissue. The features of smears of oral premalignant lesions are the keratinization growth (red, orange, brown), the increased nuclear area and so the nuclear hyperchromatism, the nuclear pleomorphism, and the chromatin clumping. All those features are essential for doing the right diagnosis. However, the oral disease should be recognized at the first view by the clinical investigation without touching the lesions avoiding possible alteration in the cells of the tissue. The current standard of incisional biopsy with histology is painful for patients and involves a delay, although histology is completed. The aim of this article is to evaluate the effectiveness of other available tests that are unobtrusive and provide immediate results like the tissue fluorescence imaging

Bone Scrapers Versus Piezoelectric Surgery in the Lateral Antrostomy for Sinus Floor Elevation

The purpose of this investigation is to evaluate 2 different methods for reducing cortical wall thickness in sinus floor augmentation surgery. A manual bone scraper was compared in terms of efficacy, speed, and safety to an ultrasonic insert for osteoplasty, in a randomized controlled clinical trial with a split-mouth design. Twenty-five patients with severe posterior maxillary atrophy were treated with bilateral sinus floor elevation with lateral approach. Antrostomies were randomly performed by eroding the cortical wall with a manual bone scraper (test site) or with an ultrasonic insert (control site) until the membrane was visible under a thin layer of bone, before outlining the window with a piezoelectric device. Occurrence of membrane perforation, laceration of vascular branches, and surgical time were recorded. Mean surgical time of the antrostomy in the test sites was 9'18", while in the control sites was 9'47". No significant differences were found in terms of surgical time, incidence of membrane perforation during antrostomy (4.3% in both groups), or other intraoperative complications between the 2 techniques. Both surgical approaches represent effective options for performing lateral antrostomies during sinus floor elevation procedures in a safe and predictable way

Histomorhological and clinical evaluation of maxillary alveolar ridge reconstruction after craniofacial trauma by applying combination of allogeneic and autogenous bone graft

A variety of techniques and materials for the rehabilitation and reconstruction of traumatized maxillary ridges prior to dental implants placement have been described in literature. Autogenous bone grafting is considered ideal by many researchers and it still remains the most predictable and documented method. The aim of this report is to underline the effectiveness of using allogeneic bone graft for managing maxillofacial trauma. A case of a 30-year-old male with severely atrophic maxillary ridge as a consequence of complex craniofacial injury is presented here. Augmentation procedure in two stages was performed using allogeneic and autogenous bone grafts in different areas of the osseous defect. Four months after grafting, during the implants placement surgery, samples of both sectors were withdrawn and submitted to histological evaluation. On the examination of the specimens, treated by hematoxylin and eosin staining, the morphology of integrated allogeneic bone grafts was revealed to be similar to the autologous bone. Our clinical experience shows how the allogeneic bone graft presented normal bone tissue architecture and is highly vascularized, and it can be used for reconstruction of severe trauma of the maxilla

Protaper and waveone systems three-dimensional comparison of device parameters after the shaping technique. A micro-CT study on simulated root canals

Aim: The aim of this study is to highlights possible differences in the volume of shaping and canal surface area after the using of common endodontic devices ProTaper Universal and WaveOne systems. Methods: Forty ISO 15, 0.02 taper, S-shaped endo-training Blocks (Dentsply, Maillefer) were assigned in two groups (n = 20 for each group). For each block the initial working length (WL) was evaluated with a 10 K-files (Dentsply Maillefer), so the glide path was created with PathFile 1, 2 and 3 (Dentsply Maillefer) at the WL. After that, simulated canals in the group 1 were shaped with S1, S2, F1 and F2 at WL; while in group 2 it was used single-file WaveOne primary in reciprocating motion. After shaping, the resin blocks were analysed with Skyscan 1172 scanner (Skyscan, Kontich, Belgium) and then volumetrically at a source voltage of 65 kV and a source current of 153 uA. Results: No statistically differences (P > 0.05) have been found in terms of volume and surface area after the use of ProTaper Universal and WaveOne systems. Conclusions: Although, results from micro-CT analysis revealed that Wave One result in a decrease of volume and surface area of shaping than ProTaper Universal, differences are not statistically significant

Oral and dental health of Italian drug addicted in methadone treatment

Objectives: Our group recorded the characteristic of oro-dental health among a group of drug addicts in recovery treatment with methadone, and it evaluated the changes related to the withdrawal therapy. Methodology: A sample of 50 drug addicts in treatment with methadone was included in this study. At the beginning of the withdrawal therapy, the authors recorded the parameters involved in the most common oral diseases. Moreover, it was evaluated how, during the rehabilitation protocol, the behavioral parameters and the xerostomia that influence the oral health changed. A medical history especially referring to drug addiction features was made. An intraoral objective exam was done for each patient, at the beginning of the therapy and after 3 and 6 months. Results: 82% of the subjects showed a DMFT > 0. No patient showed any presences of previous restorative therapies. Lowenthal's caries, mostly localized in the cervical upper maxillary incisor, were found in 12% of the subjects. The Löe and Silness index showed marginal gingivitis in 95% of subjects, whereas 44% showed improper occlusion and/or parafunctional habits. 52% of the subjects had a normal diet, but a qualitative evaluation showed a high percentage (48%) of immoderate refined sugars use. Xerostomia, that was present in 72% of patients during the drug dependence period, showed a marked reduction in the withdrawal period. Conclusion: The group analyzed made a combined use with other drugs. They showed a high rate of caries and marginal periodontitis. The statistical analysis of the data proves how the methadone rehabilitation program is effective even on the oral health. It will show its effects over two different time related phases: after a first phase of decreased attention to oral health (0-3 months), all index will increase in the long term (3-6 months). The rehabilitation program contributes to an improved oral health of drug addicts

ProTaper and WaveOne systems three-dimensional comparison of device parameters after the shaping technique. A micro-CT study on simulated root canals

AIM: The aim of this study is to highlights possible differences in the volume of shaping and canal surface area after the using of common endodontic devices ProTaper Universal and WaveOne systems. METHODS: Forty ISO 15, 0.02 taper, S-shaped endo-training Blocks (Dentsply, Maillefer) were assigned in two groups (n = 20 for each group). For each block the initial working length (WL) was evaluated with a 10 K-files (Dentsply Maillefer), so the glide path was created with PathFile 1, 2 and 3 (Dentsply Maillefer) at the WL. After that, simulated canals in the group 1 were shaped with S1, S2, F1 and F2 at WL; while in group 2 it was used single-file WaveOne primary in reciprocating motion. After shaping, the resin blocks were analysed with Skyscan 1172 scanner (Skyscan, Kontich, Belgium) and then volumetrically at a source voltage of 65 kV and a source current of 153 uA. RESULTS: No statistically differences (P > 0.05) have been found in terms of volume and surface area after the use of ProTaper Universal and WaveOne systems. CONCLUSIONS: Although, results from micro-CT analysis revealed that Wave One result in a decrease of volume and surface area of shaping than ProTaper Universal, differences are not statistically significant