Nuove metodologie per la valutazione della fatica ciclica di strumenti endodontici

La frattura intracanalare degli strumenti rotanti in Nichel Titanio (Ni-Ti) è ancora uno dei maggiori problemi nella pratica endodontica quotidiana, problema che frena molti neofiti nell’utilizzo costante degli strumenti rotanti stessi. Il fattore determinante per quanto riguarda gli stress di fatica ciclica, nonostante le notevoli migliorie nel disegno e nel trattamento termico degli strumenti in Nichel-Titanio, è senza dubbio la configurazione anatomica dell’endodonto. Scopo del presente studio è quello di validare un nuovo device tridimensionale per la valutazione degli stress flessurali degli strumenti rotanti in Ni-Ti. Inoltre si vuole comparare la resistenza alla fatica ciclica in due canali simili con curvature bi e tri-dimensionali

Minimally Invasive Video-Assisted Parathyroidectomy: Lesson Learned from 137 cases

Abstract: Background: Since February 1997, a technique of minimally invasive video-assisted parathyroidectomy (MIVAP) was developed at our institution for the treatment of sporadic primary hyperparathyroidism (sPHPT). In this study we analyzed the entire series of patients who underwent MIVAP during the last 3 years. Study Design: One hundred thirty-seven patients with sPHPT were selected for MIVAP. Selection criteria were: diagnosis of single adenoma based on preoperative localization studies (ultrasonography, sestamibi scintigraphy, or both), and no previous neck surgery or concomitant large multinodular goiter. The procedure, already described, is performed by a gasless video-assisted technique through a single 1.5-cm central skin incision above the sternal notch. Quick, intraoperative parathyroid hormone assay was used in 134 cases (97.8%) to confirm the complete removal of all hyperfunctioning parathyroid tissue. Results: Mean operative time was 54.3 +/- 22.6 minutes. The conversion rate was 8.8%. One laryngeal nerve palsy was registered (0.7%), as was one case of persistent hyperparathyroidism. In six patients (4.4%) a transient symptomatic postoperative hypocalcemia was observed. Two thyroid lobectomies were associated using the same minimally invasive access. At a mean followup of 15.4 +/- 10.6 months, all but two patients were normocalcemic. The cosmetic result was considered excellent by most of the patients (92.8%). Conclusions: Although not all patients with sPHPT are eligible for MIVAP, this approach can now be proposed in a bigger proportion (67% of patients). As already demonstrated in a previous study, also in a large series of patients, after greater experience has been achieved, the results and the operative time are the same as in traditional surgery, with better cosmetic result and a less painful course. (J Am Coll Surg 2000; 191:613-618. (C) 2000 by the American College of Surgeons)

In vitro evaluation of carrier based obturation technique: a CBCT study

AIM: The goal of the study was to compare the ability of two different carrier based obturation (CBO) techniques to reach working length and fill in three-dimensions root canal systems, by using CBCT. MATERIALS AND METHODS: Twenty-six extracted molars were scanned with CBCT and 40 curved canals were selected (between 30° and 90°) and divided in two similar groups (n=20). All canals were prepared up to size 25 taper .06 using nickel-titanium instrumentation. The canals in the Group SC were obturated using Soft-Core obturators (Kerr, Romulus, Mi, USA), while Group TH canals (n= 20) were obturated using Thermafil Endodontic Obturators (Tulsa Dental Products, Tulsa, OK, USA), strictly following manufacturers' instructions for use. The obturations were analyzed by means of CBCT to measure the distance from the apical limit of obturation to the apical foramen and the presence of voids inside root canals. RESULTS: There was no significant difference between the two groups in the mean distance of the apical extent of the obturation (t test, p>0.05). Overfilling occurred in only 3 cases (2 in Group TH and 1 in Group SC). The percentages of voids in both groups were very low with no significant difference (Z test, p>0.05). CONCLUSIONS: The two tested CBO techniques showed similar positive results in terms of performance, even if, after checking with verifiers, in most cases the size of the selected Soft-Core obturator was one size smaller than Thermafil

One-stage laser-microtextured implants immediately placed in the inter-radicular septum of molar fresh extraction sockets associated with GBR technique. A case series study

The outcome of one-stage trans-mucosal immediate implants with simultaneous guided bone regeneration (GBR) technique has become highly predictable. Furthermore, when this approach is performed to place one-stage implants into the inter-radicular septum of fresh extraction sockets in the molar region, the risk of incorrect emergence profile and off-angle loading is reduced. The aim of the present study was to clinically evaluate the horizontal hard and soft tissue changes, and radiographically the vertical socket walls remodeling, and the early peri-implant marginal bone loss (EMBL) following the placement of immediate one-stage implants in the inter-radicular septum of molar fresh extraction sockets, associated with a collagen membrane. Twenty patients were selected to receive a one-stage implant with laser-microtextured collar surface into the inter-radicular septum of a fresh molar extraction sockets, associated with a simultaneous placement of a collagen membrane. Intraoral radiographs and model casts were used for the evaluation. Correlation between the amount of the keratinized tissue thickness (KTT) with EMBL was also analyzed. After 4 months, the vertical radiographic mesial and distal EMBL around implants was of 0.06 ±0.01 mm and 0.04±0.02 mm, respectively, with no statistically significant difference between T0 and T1 (P >0.05). No statistical differences were found also for each radiographic measure used for the examination of implant sites vertical bone changes (p >0.05). Clinically, horizontal changes of the bucco-lingual central width were found statistically significant (p0.05). In addition, no statistically significant correlation between EMBL and the amount of KTT was found (P >0.05). Results suggest that the immediate placement of one-stage laser-microtextured implants could provide advantages in preserving the extraction socket?s hard and soft tissue remodeling, and the peri-implant marginal bone level before the prosthetic loading

Detection of bone defects using CBCT exam in an Italian population

Background. The aim of this study was to evaluate the in vivo incidence and the location of fenestrations in a young Italian population by using CBCT. Materials and Methods. Fifty patients who had previously performed CBCT for planning third molar extraction or orthodontic therapy were selected for the study. No previous dental treatment had been performed on these patients. Overall, 1,395 teeth were evaluated. Root fenestrations were identified according to the definition of Davies and the American Association of Endodontists. Data was collected and statistically analyzed. Results. Fenestrations were observed in 159 teeth out of 1,395 (11% of teeth). In the lower jaw, we found 68 fenestrations (5%) and 91 in the maxilla (6,5%). Incisors were the teeth with the highest incidence of fenestrations. Conclusion.The relative common finding (11%)of fenestration supports the need for CBCT exams before any surgical/implant treatment to avoid complications related to the initial presence of fenestrations. CBCT was found to be an effective and convenient tool for diagnosing fenestration

The influence of a new clinical motion for endodontic instruments on the incidence of postoperative pain

Previous studies showed that motor motions play an important role in determining apical extrusion of debris. Therefore a new clinical motion (MIMERACI) has been proposed. The basic idea is to progress slowly (1mm advancement), and after each 1mm, to remove the instrument from the canal, clean flutes and irrigate. The aim of the study was to prove whether the clinical use of MIMERACI technique would influence or not postoperative pain.MATERIALS AND METHODS: 100 teeth requesting endodontic treatment were selected for the study and divided into two similar groups based on anatomy, pre-operative symptoms and vitality, presence or absence of periapical lesion. All teeth were shaped, cleaned and obturated by the same operator, using the same NiTi instruments. The only difference between the two groups was the instrumentation technique: tradional (group A) vs MIMERACI (group B). Assessment of postoperative pain was performed 3 days after treatment. Presence, absence and degree of pain were recorded with a visual analogue scale (VAS), validated in previous studies. Collected data statistically analyzed using one-way ANOVA post hoc Tukey test. RESULTS: For VAS pain scores MIMERACI technique showed significantly better results than group A (p=0,031). Overall, both incidence and intensity of symptoms were significantly lower. Flare ups occurred in 3 patients, but none treated with the MIMERACI Technique. CONCLUSIONS: Since extruded debris can elicit more postoperative pain, results obtained by using MIMERACI technique are probably due to many factors: better mechanical removal and less production of debris and more efficient irrigation during instrumentation

Immediate non-submerged implants with laser-microtextured collar placed in the inter-radicular septum of mandibular molar extraction sockets associated to GBR : results at 3-year

Background: The aim of the present study was to radiographically evaluate the vertical socket walls changes, and the peri-implant marginal bone remodelling, and clinicallly the soft tissues conditions around the non-submerged single implants placed into the inter radicular septum of mandibular molar sockets, associated with a collagen membrane, after 3 years of loading.Material and Methods: Thirty patients underwent to placement of a non-submerged implants with a laser-micro-textured collar into the inter radicular septum of mandibular molar fresh extraction sockets. A collagen membrane and the mucoperiosteal flap were adapted around the neck of the implants, leaving the laser-microtextured collar to heal in a transmucosal fashion. Results: At the end of the follow-up period, no statistical differences were found for each radiographic measure-ments used for the examination of extraction sockets vertical bone changes. Compared to implants placement, at the end of the 3-year follow-up, the vertical radiographic mesial and distal peri-implant marginal bone levels showed a statistically significant gain of 0.9 (SD 0.5), and 1.0 mm (SD 0.6), respectively (P=0.037).Conclusions: in mandibular fresh extraction sockets, the method of GBR around transmucosal implants with la-ser-microtextured surface placed into the interadicular septum may be used successfully to counteract the ridge remodelling

Full arch fixed prostheses vs. full arch telescopic-retained retrievable prostheses both supported by implants and natural tooth abutments in periodontally treated patients : results at 15 years

The clinical outcome of full arch fixed prostheses vs. full arch telescopic-retained retrievable prostheses supported by implants and natural tooth abutments in periodontally treated patients has been reported by few studies, with controversial results. The objective of this study was to evaluate long-term (15 years) complications of abutment teeth and dental implants in periodontally treated patients, rehabilitated with full arch telescopic-retained retrievable prostheses (TRP)s vs. full arch fixed prostheses (FP)s supported by teeth and implants. After active periodontal therapy (non-surgical and surgical), and implant placement (replacement of hopeless teeth and in edentulous sites), 18 patients were rehabilitated in both dental arches with full arch TRPs, and 17 patients were rehabilitated with full arch FPs. Patients were annually recalled for technical and/or biological complications monitoring. During the 15-year observation period, 29 of 164 (17.6%) implants failed in the TRP group and 26 of 152 (17.1 %) implants in the FP group. Due to progression of periodontal disease, endo-perio untreatable lesion and caries, 22 of 233 abutment teeth were extracted (8.1) % in the TRP group and 23 of 221 (10.4%) abutment teeth were extracted in the FP group. Difference in implant failures and abutment teeth loss between the two groups were found not statistically significant (p >0.05). Poisson regression analysis showed that in both groups, factors such as smoking habits, FMBS>20, number of pockets >6 mm, mean bone loss, and bone loss/age, contribute to tooth and implant failure (p<0.05). In this clinical study, in periodontally treated patients, full arch telescopic-retained retrievable prostheses, and full arch fixed prosthesis, supported by teeth and implants presented comparable long-term results of tooth loss and implant failure, if regular periodontal therapy is implemented

Antineoplastic Effects of PPARγ Agonists, with a Special Focus on Thyroid Cancer

Peroxisome Proliferator-Activated Receptor-γ (PPARγ) is a ligand-activated nuclear hormone receptor that functions as transcription factor and plays an important role in lipid metabolism and insulin sensitization. Recent studies have shown that PPARγ is overexpressed in many tumor types, including cancers of breast, lung, pancreas, colon, glioblastoma, prostate and thyroid differentiated/anaplastic cancers. These data suggest a role of PPARγ in tumor development and/or progression. PPARγ is emerging as a growth-limiting and differentiation-promoting factor, and it exerts a tumor suppressor role. Moreover, naturally-occurring and synthetic PPARγ agonists promote growth inhibition and apoptosis. Thiazolidinediones (TZDs) are synthetic agonists of PPARγ that were developed to treat type II diabetes. These compounds also display anticancer effects which appear mainly to be independent of their PPARγ agonist activity. Various preclinical and clinical studies strongly suggest a role for TZDs both alone and in combination with existing chemotherapeutic agents, for the treatment of cancer. Differentiation therapy involves the use of agents with the ability to induce differentiation in cells that have lost this ability, i.e. cancer cells, targeting pathways capable of re-activating blocked terminal differentiation programs. PPARγ agonists have been shown to induce differentiation in solid tumors such as thyroid differentiated/ anaplastic cancers and sarcomas. However, emerging data suggest that chronic use of TZDs is associated with increased risk of adverse cardiovascular events. The exploration of newer PPARγ agonists can help in unveiling the underlying mechanisms of these drugs, providing new molecules that are able to treat cancer, without increasing the cardiovascular risk of neoplastic patients