Regenerative Endodontic Therapy using a New Antibacterial Root Canal Cleanser in necrotic immature permanent teeth: Report of two cases treated in a single appointment.

A case of regenerative endodontics: (a) before treatment; (b) post-treatment Xray; (c) follow-up at 6 months; (d) follow-up at 12 months.

The effects of a new decontaminant solution on root canal bleeding during endodontic treatment: a randomized controlled study.

Blood contamination of the canal during preparation and obturation can be a problem in Endodontics; this may result in apical microleakage. The purpose of this investigation was to observe and evaluate the hemostatic properties of biofilm decontaminant material (sulfonic/sulphuric acid solution, HybenX, EPIEN Medical) used in teeth with necrotic pulp and unstoppable bleeding after root canal shaping. A prospective study was designed with 2 randomized parallel groups: decontaminant material (experimental group) and sodium hypochlorite 5% (control group). The analysis of the root canal bleeding was evaluated by the clinician before and after the application of the sulfonic/sulphuric solution or sodium hypochlorite 5%, by measuring the millimeters of blood on a sterile paper point introduced in the root canal. Sixty patients with necrotic pulp and unstoppable bleeding were enrolled in this study and randomly divided into 2 groups: decontaminant material in 30 patients (experimental group) or sodium hypochlorite 5% in 30 patients (control group). T-test showed that the percentage change in millimeters of blood detected in the root canal was statistically greater for experimental group [mean difference: 0.74 (IC: 0.66-0.82); p less than 0.0001]. The hemostatic properties were better in the experimental group than in the sodium hypochlorite 5% group (control). Further research may be needed to confirm the results of this study..

A diagnostic dilemma: endodontic lesion or odontogenic keratocyst? A case presentation.

AIM: To present a clinical case of odontogenic keratocyst (OKC) simulating a lateral periodontal cyst. SUMMARY: A 39-year-old female complaining of swelling and pain in the left mandibular premolar area was found to have a radiolucent lesion between teeth 34 and 35 (FDI). Both teeth had incomplete root fillings, and orthograde re-treatment of both premolars was performed. At 2-year follow-up, radiographic examination showed an increase in the radiolucent defect with respect to the previous examination. A surgical treatment of tooth 34 was then performed, with histological examination of the lesion. Histological features were consistent with an OKC, and the lesion was successfully treated by complete enucleation and application of Carnoy's solution. At 2-year follow-up, no clinical signs or symptoms were found and the radiolucent area had disappeared. KEY LEARNING POINTS: Odontogenic keratocysts may mimic endodontic lesions. Clinicians should carefully review their cases and consider surgical intervention with biopsy in cases that do not heal.

Mineral trioxide aggregate in the treatment of external invasive resorption: a case report.

AIM: To describe the management of external invasive resorption using mineral trioxide aggregate (MTA). SUMMARY: External invasive root resorption may occur as a consequence of trauma, orthodontic treatment, intracoronal bleaching and surgical procedures, and may lead to the progressive and destructive loss of tooth structure. Depending on the extent of the resorptive process, different treatment regimens have been proposed. A 19-year-old male patient presented with tooth 11 (FDI) showing signs and symptoms of irreversible pulpitis, external invasive resorption and periodontal pocket on the disto-palatal. After root canal treatment, the defect was accessed coronally. The resorption area was chemo-mechanically debrided using ultrasonic tips and irrigant solution. MTA was used to fill the resorptive defect, and the coronal access was temporarily sealed. The definitive coronal restoration was performed after 3 days. Radiographs at 1, 2 and 4 years showed adequate repair of the resorption and endodontic success. Clinically, the tooth was asymptomatic, and no periodontal pocket was found. KEY LEARNING POINTS: *Mineral trioxide aggregate was successfully used to restore a small area of external invasive resorption. *A coronal approach can sometimes be successfully used in order to avoid surgery and periodontal complications.

Apical plug technique using mineral trioxide aggregate: results from a case series.

AIM: To examine the clinical and radiographic appearance of teeth that suffered premature interruption of root development and were treated by an mineral trioxide aggregate (MTA) apical plug technique. SUMMARY: Eleven teeth with immature root apices in 11 patients were treated nonsurgically by the manual application of MTA in the apical portion of the root canal under microscopic vision. Follow-up evaluations were performed at 1-2 years after treatment. KEY LEARNING POINTS: Mineral trioxide aggregate appears to be a valid material to obtain periradicular healing in teeth with open apices and necrotic pulps. Ten out of 11 cases were associated with periradicular health at follow-up evaluation.

The percentage of gutta-percha-filled area in simulated curved canals when filled using Endo Twinn, a new heat device source.

AIM: To compare the percentage of gutta-percha-filled area (PGP) in simulated root canals when varying the penetration depth and function of the pluggers (heat versus heat plus vibration) using Endo Twinn. METHODOLOGY: Sixty-four resin blocks with simulated 34-35 degrees curved canals were randomly divided into two groups in order to obtain two canal shapes: group A with 0.8 taper and group B with 0.4 taper. The apical portion of each canal was prepared to a size 20 K-file. The canals were filled with gutta-percha in combination with a root canal sealer. In each group 16 canals were filled using the Endo Twinn heat function and 16 canals by means of both the heat and the vibration function. All samples were sectioned horizontally at three levels (1.25, 2.5 and 4.0 mm from the working length) and the PGP was measured. Data were analysed using ANOVA test. RESULTS: At the 1.25 mm level PGP was significantly greater using the vibration function (P = 0.0329) and in 0.8 taper canals (P < 0.0001). At the 2.5 mm level the PGP was greater in the canals with 0.8 taper compared with a 0.4 taper with or without vibration (vibration, P = 0.0056; interaction taper-vibration, P = 0.0020). In 0.4 taper canals the PGP was greater when the vibration function was activated. At the 4 mm level in 0.8 taper canals there was no significant difference in PGP with or without the vibration (P = 0.6742). CONCLUSIONS: 0.8 taper canals had significantly greater PGP than 0.4 taper canals. At the 1.25 mm level there was significantly greater PGP when the vibration function was activated.

A SEM study of in vivo accuracy of the Root ZX electronic apex locator.

Twenty-nine unprepared, vital teeth were used to evaluate the accuracy of the Root ZX in locating the root canal foramen. After extraction of the teeth, a scanning electron microscope analyzed the relation of the file tip to the foramen. The sample was divided into two groups (Group A and Group B) according to the presence of a normal apical foramen (along the root main axis) or of a lateral foramen (deviating from the root main axis). With a tolerance level of +/- 0.5 mm, a clinical accuracy rate of 82.75% was recorded in the total sample. With a +/- 1.0-mm tolerance level, an accuracy of 100% was found. The error in locating the apex was significantly smaller in cases with a normal apical foramen (Group A) than in cases with a lateral foramen (Group B) (p < 0.001). An accuracy of 100% at the +/- 0.5-mm tolerance level was registered in Group A.

[Localization of the apical foramen using the newest electronic instruments: stereomicroscopy and SEM (scanning electron microscopy)]. / La localizzazione del forame apicale con strumenti elettronici di ultima generazione: analisi allo stereomicroscopio e al MES.

Introduction of double impedence as new parameter in root canal length electronic measurement allowed first and second generation electronic apical localizers main problems overcoming: precision failure in presence of conducting fluids. Our study's purpose was an in vitro evaluation of two third generation instruments (Apit-Osada and Root ZX-Morita Corp.) ability in apical foramen localization using sodium hypoclorite as irrigating solution. 40 human monorooted teeth with immature apex were studied. 20 samples were measured by Apit and 20 by Root ZX; measurements were recorded when apical foramen was reached. Samples were fixed for stereomicroscope observation before and after apical 3 mm worn and prepared for SEM observation. Evaluations about each system's precision were made by calculating difference between foramen position determined by electronic localizer and its real anatomical position determined by a computed image analizing system linked to SEM. All measurements were included between a minimum value of -0.45 mm and a maximum value of 0.26 mm. Mann Whithney U test was performed to compare average values of the two sample groups but his was not meaningful (p = 0.18) showing that there is no valuable difference in accuracy between Apit and Root ZX. According to most researchers, who consider a +/- 0.5 mm error range clinically acceptable, and considering that in vitro measurements never exceded this limit value we conclude confirming both instruments' safety.

[The ultrastructural aspects of the carious lesion]. / Aspetti ultrastrutturali della lesione cariosa.

The aim of the present study was to analyse under SEM the ultrastructural alterations in tubular content and peri- and intertubular dentin in teeth subject to active carious lesions. The samples used were teeth with grade 2 active carious lesions without signs of abrasion, wear, erosion and conservative reconstruction. The coronal fragments obtained by fracture were fixated, dehydrated and metallized before SEM analysis. The study was performed by analysing samples of amelo-dentinal junctions towards the pulpo-dentinal edge. By correlating histopathological lesions to their topographical distribution and to the physiopathological mechanisms involved, it was possible to subdivide dentin underlying a carious lesion into three main zones: demineralisation zone, sclerosis zone, subsclerotic dentin zone. The individualization of these sectors was based on the identification of basic lesions linked to changes in tubular lumen and peri and intertubular dentin. The demineralisation zone was in fact characterised by: dentinal infection and reversal of normal tissue morphology in the outermost layers; the fibrous appearance of intertubular dentin and disappearance of peritubular dentin; modifications in the tubular content secondary to demineralisation, such as sheaths, hollow rods and intratubular crystals. The sclerosis zone was characterised by: fully occluded tubules, tubules fully occluded by rods, tubules partially occluded by hollow rods and by thickening of peritubular dentin. The third zone was the result of tissue-forming activity on the pulpodentinal edge in response to carious lesions and was represented by regular and irregular tertiary dentin. From an analysis of all data collected it is possible to hypothesize that changes in the demineralisation zone are the results of a passive tissue response exclusively linked to physicochemical mechanisms; whereas those in the sclerosis zone are due to the realisation of a lithogenic environment of multifactorial genesis at a intratubular level. The site in which there is the greatest probability of observing a cellular response is the subsclerotic dentinal zone.

[Tubular sclerosis]. / In tema di sclerosi tubulare.

Tubular sclerosis is a pulp-dentin complex defensive response to several physiologic and pathologic stimuli; it leads to an increasing tubular obliteration which enormously reduces dentinal permeability. Its typical structural features are either increased peritubular dentin thickness or "caries crystals". Pathogenesis is a much debated question: some authors assert that peritubular dentin thickening is the main liable for sclerosis while others support a centrifugal theory. Another point of view considers its pathogenesis the result of many integrated mechanism.

[A scanning electron microscope assessment of the changes induced by wear on subsonic endodontic instruments]. / Valutazione al MES delle modificazioni indotte dall'uso di strumenti endodontici subsonici.

The aim of the present work was to study the wear of a special kind of subsonic instruments with usage. We have examined with scanning electron microscope new and used instruments: the first to estimate the features and degree of final touches; the second to examine how they wear after 1, 3 and 5 minutes. We tested for each period 3 instruments per size. In all we controlled 72 instruments. The results of the study show that after 5 minutes the instruments are very worn.

[Preliminary research on the prognosis of late reimplants with prior conditioning with a fluoridated solution]. / Ricerca preliminare sulla prognosi con reimpianti tardivi previo condizionamento con soluzione fluorurata.

The principal factors that affect the prognosis of a posttraumatic reimplantation are the length of the extra-alveolar persistence and the manner in which the extracted tooth is preserved. Both are fundamental for the maintenance of the fiber vitality of the periodontal ligament. The necrosis of these fibers cause ankylosis. It is observed that the conditioning of the radicular surface with fluoride solutions before the reimplantation is likely to slow down the evolution of radicular resorption. To evaluate the effectiveness of such methodology six cases of traumatic extractions, characterized by a length of extra-alveolar persistency (not longer than 24 hours), and unfavorable conditions of the preserved tooth have been treated by conditioning the radicular surface with the Na-fluoride solution before the reimplantation. Another group of reimplantation cases with the same characteristics have been examined without proceeding first to the radicular conditioning. The results of the study, although preliminary, verified the positive influence of the Na fluoride upon the radicular resorption.

[The lamina limitans. Its scanning electron microscopic aspects]. / La lamina limitante. Aspetti al microscopio elettronico a scansione.

Many researches agree in maintaining that all the membraneous structure visible in the most external parts of the dental tubules must be considered not ad cytoplasmatic membranes of the odontoblastic processes but as an extracellular organic matrix which in certain conditions may appear detached from the internal wall of the tubule and simulated a superimposable aspect like that of an odontoblastic extension. The aim of this study was to examine at the SEM the state of this organic component in normal conditions and after demineralization with citric acid. Therefore the entire teeth of young people were fixed in formalin and dissected by fracturing. Some of the samples were demineralized with a citric acid solution. All the samples were dehydrated and metallized for the observation at SEM. Demineralization made the peritubular dentine disappear and expose inside every tubule a sheet-like structure which extended all along the tubules. The samples which were not demineralized did not demonstrate a similar structure because of their tight adhesion to the internal wall surface. This kind of formation which other researchers calls "lamina limitans" because of its high content of glycosaminoglycans might be a key factor in controlling the formation of peritubular dentine and tubular sclerosis and it will surely lead to further interesting research.

[Clinical experience with a new microfilled composite]. / Experiencias clínicas con un nuevo composite microparticulado.

The authors have investigated a new material for esthetic restoration for front teeth. It is a microfilled heterogene composite (Helio Progress) with spheridal prepolymer. The clinical trials were realized in cavities III, IV an V, in anomal y teeth and resin ceramic (with a pretreatment with silane). The results after 18 months have demonstrated the better characteristics of this material in relation with foreknown ones.

The intercellular substance of the pulp of human, fully erupted, permanent premolar teeth.

The intercellular substance of the pulp of fully erupted, healthy, human permanent premolar teeth was studied by light microscopy. Histological and histochemical methods were applied to sections from whole, decalcified teeth and isolated, undecalcified pulps, fixed with phosphate-buffered formalin and embedded in paraplast. Fibres were mainly collagen; they formed a meshwork progressively more dense from the crown to the root apex; in the crown the fibre meshwork was denser at the periphery than in the center of the pulp. Coarse bundles of collagen fibres were found in the apical part of the pulp of about one every third teeth. Glycoproteins, recognized thanks to their P.A.S. positivity, were abundant in the basal membranes of vessels and nerve fibres and between odontoblasts, but scarce in the remaining pulp tissue. Glycosaminoglycans, recognized thanks to their alcianophilia, were more abundant in the vessel wall and in the areas with coarse bundles of collagen fibres than elsewhere in the pulp; also, they were more abundant at the periphery than in the center of the pulp. As judged by staining with alcian blue at critical electrolyte concentration, glycosaminoglycans were mostly hyaluronate, with low amounts of condroitinsulphate and dermatansulphate; some heparansulphate or keratansulphate was present only in the regions with coarse bundles of collagen fibres. The morphological and histochemical differences found among different regions of each pulp and among different pulps as well provide a basis to recognize and interpret inter-regional and inter-individual variations in the pulp response to physiological and pathological modifications affecting the hard tissues of the teeth.