1,721,120 research outputs found
Perdita di volume osseo nel mascellare posteriore
No full textLa riabilitazione a supporto implantare del mascellare posteriore edentulo presenta spesso problematiche relative alla limitata dimensione verticale e alla scarsa densità dell’osso crestale residuo.
Tuttavia, grazie agli sviluppi delle moderne tecniche di implantologia, è oggi possibile sia inserire impianti nel limitato volume osseo a disposizione, sia ricorrere a tecniche rigenerative che consentano di recuperare l’osso perduto.
Questo testo fornisce un’approfondita analisi del piano di trattamento e delle varie opzioni chirurgiche e protesiche disponibili: ogni capitolo contiene dettagliate informazioni, basate sulla più recente evidenza scientifica, sui passaggi diagnostici e terapeutici necessari per raggiungere e mantenere nel tempo risultati clinici ottimali.
Le opzioni minimamente invasive rappresentate dall’utilizzo di impianti corti o inclinati sono affrontate in modo approfondito, fornendo suggerimenti pratici di carattere chirurgico e protesico che possono contribuire positivamente a una prognosi favorevole.
Sono inoltre descritte step-by-step le tecniche chirurgiche di rialzo del seno mascellare con approccio laterale e transcrestale, presentando quindi un razionale biologico che sia di ausilio per il clinico nella scelta fra i diversi approcci chirurgici e fra i diversi biomateriali utilizzabili in questa procedura clinica, evidenziando vantaggi e svantaggi delle varie tipologie disponibili
AN EX VIVO COMPARISON OF THREE DIFFERENT GUTTA-PERCHA CONES WHEN COMPACTED AT DIFFERENT TEMPERATURES: RHEOLOGICAL CONSIDERATIONS IN RELATION TO THE FILLING OF LATERAL CANALS
No full textAim To compare ex vivo the penetration of three brands of gutta-percha cones, compacted under a constant force and heated to different temperatures, into artificial lateral canals. Methodology Resin blocks with simulated main canals, each having two lateral canals (C at 6.5 and A at 13 mm from the surface of the resin block), were selected. A gutta-percha cone, either Mynol MF, Hygenic MF or GT Tulsa 0.04 was compacted into each main canal for 5 s using a wire rod with a diameter of 0.7 mm soldered to the bottom of a metal cylinder, with a force of 2.7 kg at controlled temperatures of 37, 42, 47, 52, 60 degrees C. The penetration of each brand of gutta-percha into 60 lateral canals (10 at each temperature) was measured using a stereomicroscope. Statistical analysis was performed using the ANOVA, the Scheffe test and the t-test. Results None of the three brands of cones entered up to 0.1 mm within either lateral canal until a temperature of 47 degrees C was reached; at that temperature only Mynol cones (P <= 0.05) penetrated in four of 10 A-level canals (mean 0.13 +/- 0.19 mm) and in all 10 C-level canals (mean 0.43 +/- 0.12 mm). The A-level lateral canals were penetrated at 52 degrees C by Mynol cones (mean 0.76 +/- 0.34 mm) to a significantly greater distance (P <= 0.05) than Tulsa cones (mean 0.31 +/- 0.12 mm) and Hygenic cones (mean 0.11 +/- 0.08 mm). At 60 degrees C the Mynol cones (mean 1.93 +/- 0.34 mm) penetrated significantly more (P <= 0.05) than the Tulsa cones (mean 0.86 +/- 0.22 mm) and Hygenic cones (mean 0.67 +/- 0.19 mm). The C-level lateral canals were penetrated at 52 degrees C by Mynol cones (mean 0.91 +/- 0.29 mm) to a significantly greater distance (P <= 0.05) than Tulsa cones (mean 0.47 +/- 0.16 mm) and Hygenic cones (mean 0.46 +/- 0.15 mm), whilst no significant difference was found at 60 degrees C. Conclusions When heated and compacted, the three gutta-percha cones penetrated the lateral canals to different degrees. They penetrated more than 0.43 mm into the lateral canals only at temperatures higher than 47 degrees C
Retracted publications and their citation in dental literature: A systematic review
Get PDFObjectives: The present systematic review aimed to perform an in-depth analysis of the different features of retracted publications in the dental field. Material and methods: This review has been recorded in the PROSPERO database (CRD42017075634). Two independent reviewers performed an electronic search (Pubmed, Retraction Watch) for retracted articles in dental literature up to December 31, 2018. Results: 180 retracted papers were identified, the first published in 2001. Retractions increased by 47% in the last four-year period (2014–2018), when compared with 2009–2013 (94 and 64 retracted publications, respectively). Author misconduct was the most common reason for retraction (65.0%), followed by honest scientific errors (12.2%) and publisher-related issues (10.6%). The majority of retracted research was conducted in Asia (55.6%), with 49 papers written in India (27.2%). 552 researchers (89%) are listed as authors in only one retracted article, while 10 researchers (1.6%) are present in five or more retracted publications. Retracted articles were cited 530 times after retraction: the great majority of these citations (89.6%) did not consider the existence of the retraction notice and treated data from retracted articles as reliable. Conclusions: Retractions in dental literature have constantly increased in recent years, with the majority of them due to misconduct and fraud. The publication of unreliable research has many negative consequences. Studies derived from such material are designed on potentially incorrect bases, waste funds and resources, and most importantly, increase risk of incorrect treatment for patients. Citation of retracted papers represents a major issue for the scientific community
Clinical, histologic, and histomorphometric analyses of regenerated bone in maxillary sinus augmentation using fresh frozen human bone allografts
No full textBackground: The purpose of the present study was the clinical and the histologic evaluation of fresh frozen human bone (FFB) allografts used for maxillary sinus-augmentation procedures. Methods: Ten subjects were treated with maxillary sinus augmentations using FFB. Radiologic measurements were recorded on computed tomography scans preoperatively and 5 months after the sinus surgeries. At 5 months, during implant placement, 10 core biopsies were retrieved and processed for histomorphometric evaluation under light microscopy (LM). Clinical and histomorphometric measurements are presented as mean SD. Results: At baseline, the height of the alveolar ridge measured 4.3 +/- 1.3 mm (mean); after augmentation procedures, at implant positioning, it had a mean height of 16.0 +/- 1.8 mm. All 22 dental implants were clinically healthy after 5 months. LM showed that most of the specimens presented newly formed bone that was completely integrated with preexisting bone. The interface areas between new and old bone were not discernible. Woven bone was present in some areas of the biopsies; however, in the majority of the examined regions, there was mature osseous tissue presenting features of trabecular bone. There was no evidence of an acute inflammatory infiltrate. Histomorphometry revealed that the percentage of bone was 48.15% +/- 14.32%, whereas marrow spaces occupied the rest of the area. Conclusion: FFB is a biocompatible material that can be successfully used for maxillary sinus augmentations without interfering with normal reparative bone processes
Efficacia di differenti sistemi di cementazione intracanalare mediante test di microtensile
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Porous titanium obtained by a new powder metallurgy technique:preliminary results of human osteoblast adhesion on surface polished substrates
No full textIntraoperative Complications during Sinus Floor Elevation Using Two Different Ultrasonic Approaches: A Two-Center, Randomized, Controlled Clinical Trial
Get PDFPurpose: The aim of this study was to assess the prevalence of intraoperative complications during maxillary sinus elevation with lateral approach using a piezoelectric device with two different surgical techniques.
Materials and Methods: Antrostomies were randomly performed by outlining a window (group A, 36 patients) or by eroding the cortical wall with a grinding insert until the membrane was visible under a thin layer of bone, before outlining the window (group B, 36 patients). Occurrence of membrane perforation, laceration of vascular branches, and surgical time was recorded.
Results: Seventy-two patients underwent sinus floor elevation: four perforations (11.1%) were observed in group A (two occurred during elevation with hand instruments) and zero perforations in group B (p < .05). No evidence of vascular lacerations was registered in both groups. A clinically insignificant but statistically shorter surgical time was recorded in group A (9.2 1 3.7 minutes) than in group B (13.3 1 2.4 minutes; p < .05).
Conclusions: Within the limits of the present study, it may be concluded that ultrasonic erosion of the lateral wall of the sinus is a more predictable technique than piezoelectric outlining of a bone window in preventing from accidental perforations of Schneiderian membrane during sinus augmentation procedures
Influence of whitening on the degree of conversion of dental adhesives on dentin
No full textThe aim of this study was to analyze the extent of polymerization of different adhesive systems on whitened dentin. One adhesive of each class was investigated: Adper Scotchbond Multi Purpose (3M ESPE); One-Step (Bisco); Clearfil Protect Bond (Kuraray); and Xeno III (Dentsply DeTrey). Dentin disks were treated with Opalescence Xtra Boost (Ultradent) for 30 min and bonded immediately after 24 h or after 14 d of storage in 100% humidity at 37 degrees C. Unbleached dentin disks were prepared as controls. The extent of polymerization of bonded interfaces was obtained with differential scanning calorimetry (DSC) at 20, 40 and 60 s, and the data were statistically analyzed. The extent of polymerization obtained from DSC exotherms of adhesives applied immediately after whitening was significantly lower compared with controls. An increased extent of polymerization after storage was confirmed for all adhesives, and no difference with controls was found after 14 d. A prolonged irradiation time increased the curing rate for all the tested adhesives. This study supports the hypothesis that polymerization of the adhesive is reduced after dentin whitening and that delayed adhesive application reverses the polymerization inhibition. Prolonged polymerization intervals may counteract the inhibition of polymerization caused by the whitening procedure. Nevertheless, further in vivo studies should validate this issue
Influenza della tecnica di pretrattamento smalteo sull’infiltrazione marginale dei sigillanti
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