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1.
Oper Dent ; 45(6): 575-580, 2020 Nov 01.
Article in English | MEDLINE | ID: mdl-32503042

ABSTRACT

CLINICAL RELEVANCE: It is possible to modify the natural emergence profile of the tooth using simple intrasulcular direct restorations. The shape of the intrasulcular part of the restoration will determine the design of the gingival contour. SUMMARY: Some clinical situations, such as the closure of pronounced diastemas and the transformation of malformed, small, or peg-shaped teeth, require a rebalancing of dental proportions accompanied by a modification of the gingival contour. A traditional treatment plan might require surgical, prosthetic, and/or orthodontic treatment, but in some cases, these therapeutic options could be considered too invasive and not always the best solution. Moreover, not all patients are ready to undergo irreversible, long, and expensive procedures. To overcome these limitations and to solve all of these clinical problems in a rapid and noninvasive way, we propose a new technique that allows us to modify the natural emergence profile of the tooth using simple intrasulcular direct restorations. Using the Biologically Active Intrasulcular Restoration technique, it is possible to rebalance tooth shape and dimensions, gingival level and contour with low biological and economic costs. This method, which does not require any preparation of the dental tissues, is reversible and minimally invasive. It is applicable to patients of all ages, and results are obtained in a single appointment.


Subject(s)
Diastema , Tooth , Dental Restoration, Permanent , Gingiva , Humans
2.
Oper Dent ; 44(4): 333-335, 2019.
Article in English | MEDLINE | ID: mdl-30517068

ABSTRACT

Noncarious cervical lesions (NCCLs) are steadily increasing. Unfortunately, NCCL restorations represent one of the less durable types of restorations due to problems, including isolation and crevicular moisture control, especially in cases where the cervical margin is covered by soft tissue. This article presents a technique that allows us, through the use of a common metallic matrix, to isolate and make accessible class V cavities with intrasulcular cervical margins. The advantages and disadvantages of the technique are presented.


Subject(s)
Dental Restoration, Permanent , Tooth Cervix
3.
Oper Dent ; 37(1): 28-36, 2012.
Article in English | MEDLINE | ID: mdl-21942241

ABSTRACT

OBJECTIVES: To evaluate the compatibility between aged siloranes and methacrylate-based composites by simulating a common repair-technique. METHODS: Twenty substrates were constructed using silorane (Filtek Silorane, 3M ESPE) and methacrylate composites (Filtek Supreme XT, 3M ESPE). Substrates were aged in 0.9% NaCl solution at 37°C for 72 hours. Silorane build-ups were constructed on silorane substrates without any intermediate layer (IL). Methacrylate build-ups were constructed on silorane substrates without any IL, with a methacrylate IL (Heliobond, Ivoclar Vivadent), or with a phosphate-methacrylate IL (Silorane System Adhesive Bond, 3M ESPE). Methacrylate build-ups were also constructed on methacrylate substrates without any IL. The micro-shear bond strength test was carried out after thermocycling. Bond strength data were statistically analyzed using analysis of variance and Tukey post hoc tests. Failure modes were assessed by means of scanning electron microscopy observations. RESULTS: The silorane-methacrylate group without any IL showed the lowest bond strength values (0.4 ± 0.1 MPa). The use of a methacrylate-based IL (1.6 ± 1.7 MPa) led to a slight increase in bond strength, whereas the use of phosphate-methacrylate IL (9.1 ± 5.4 MPa) significantly increased bond strength. There was no statistically significant difference in bond strength between silorane-silorane (7.9 ± 3.6 MPa) and methacrylate-methacrylate (9.5 ± 4.1 MPa) groups without any IL.


Subject(s)
Composite Resins/chemistry , Dental Bonding/methods , Methacrylates/chemistry , Siloxanes/chemistry , Acrylates/chemistry , Acrylic Resins/chemistry , Dentin-Bonding Agents/chemistry , Humans , Materials Testing , Microscopy, Electron, Scanning , Organophosphates/chemistry , Polyethylene Glycols/chemistry , Polymethacrylic Acids/chemistry , Shear Strength , Silorane Resins , Sodium Chloride/chemistry , Stress, Mechanical , Surface Properties , Temperature , Time Factors
4.
Int Endod J ; 45(3): 249-56, 2012 Mar.
Article in English | MEDLINE | ID: mdl-22007679

ABSTRACT

AIM: To compare by means of a push-out test the interfacial strength of a dual-curing resin cement and a light-curing self-adhering resin composite when used in translucent fibre post cementation. METHODOLOGY: Thirty-four extracted human premolars with single canals were selected and root filled. Translucent fibre posts (RelyX Fiber Post) were luted into the root canal using two resinous luting systems (n = 17). Dual-Curing Technique (DC): the specimens were treated with Excite DSC and RelyX ARC, which were light-cured simultaneously through the post for 60 s. Light-Curing Self-Adhering Technique (LCSA): the specimens were treated with Vertise Flow, which was light-cured through the post for 60 s. The specimens were sectioned transversally into six slices to perform the push-out test at the coronal, middle and apical regions of the root canals. Data were analysed by two-way anova. All specimens were analysed by stereomicroscopy and SEM to determine fracture patterns. RESULTS: There were no significant differences between the DC and LCSA techniques (P = 0.703) in any of the canal regions. Root region was not a significant factor for push-out values (P = 0.255) and group-region interactions were not significant (P = 0.740). For the DC technique, the majority of the fracture patterns (73.3%) were adhesive at the interface between dual-curing resin cement and adhesive. For the LCSA technique, the majority of the fracture patterns (71.7%) were adhesive at the interface between light-curing self-adhering resin composite and dentine. CONCLUSIONS: The interfacial strength between light-curing self-adhering resin composite and root canal walls is equivalent to the interfacial strength between dual-curing cement and root canal walls.


Subject(s)
Cementation/methods , Light-Curing of Dental Adhesives/methods , Post and Core Technique/instrumentation , Resin Cements/chemistry , Self-Curing of Dental Resins/methods , Acid Etching, Dental/methods , Acrylates/chemistry , Adhesiveness , Bisphenol A-Glycidyl Methacrylate/chemistry , Composite Resins/chemistry , Dental Pulp Cavity/ultrastructure , Dental Stress Analysis/instrumentation , Dentin/ultrastructure , Dentin-Bonding Agents/chemistry , Humans , Materials Testing , Methacrylates/chemistry , Microscopy, Electron, Scanning , Phosphoric Acids/chemistry , Polyethylene Glycols/chemistry , Polymethacrylic Acids/chemistry , Root Canal Preparation/instrumentation , Root Canal Preparation/methods , Stress, Mechanical , Surface Properties , Tooth Apex/ultrastructure
5.
Minerva Stomatol ; 56(3): 129-38, 2007 Mar.
Article in English | MEDLINE | ID: mdl-17327817

ABSTRACT

One of the main problems when using resin-based composites is the resulting polymerization shrinkage stress. Composite strain is hindered every time the composite is bonded to the tooth's walls. In the pre-gel phase the shrinkage stress is reduced by the composite flow from the free to the bonded surface areas. Therefore, no stress develops at the dentine-composite interface. When a gel point is reached, the composite flow no longer compensates for the volumetric shrinkage. The generated stress may cause adhesive failure and several other adverse clinical consequences such as enamel fracture, cracked cusps, cuspal movement, microcracking of the restorative material and gaps between the resin and cavity walls which may cause secondary caries and postoperative sensitivity. A sensible use of materials in direct restorations may contribute to a reduced rate of shrinkage stress. To this aim glass-ionomer cement as well as flowable, light-curing and self-curing composites were examined. The aim of this study was to provide some useful information for a sensible choice of restoration materials in order to control shrinkage stress and its negative consequences in direct posterior restorations.


Subject(s)
Composite Resins , Dental Cements , Dental Restoration, Permanent , Materials Testing , Stress, Mechanical
6.
Int Endod J ; 39(8): 610-5, 2006 Aug.
Article in English | MEDLINE | ID: mdl-16872455

ABSTRACT

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.


Subject(s)
Dental Pulp Cavity/anatomy & histology , Gutta-Percha/therapeutic use , Root Canal Filling Materials/therapeutic use , Root Canal Obturation/methods , Gutta-Percha/chemistry , Hot Temperature/therapeutic use , Humans , Pressure , Root Canal Filling Materials/chemistry , Root Canal Obturation/instrumentation , Root Canal Preparation/methods , Surface Properties , Vibration/therapeutic use
7.
Minerva Stomatol ; 54(7-8): 415-28, 2005.
Article in English, Italian | MEDLINE | ID: mdl-16211000

ABSTRACT

AIM: Recently, there has been a tendency to simplify bonding procedures. Current self-etching adhesives combine conditioning, priming and bonding functions thus reducing technique-sensitivity as well as the risk of making errors. Another important advantage of this approach is that it allows the resin to etch and infiltrate the substratum simultaneously thus reducing the risk of any discrepancy between these 2 processes. The aim of this study was to evaluate the bonding quality of 4 self-etching adhesives both on dentin and enamel using SEM analysis. METHODS: Twenty caries-free molars were used. The aprismatic enamel layer was removed from the internal and external slopes of the vestibular cusps using a diamond bur. Each molar was then transversally cut just above the pulp chamber using a diamond saw (composhave 4255 Intensiv) thus obtaining twenty coronal fragments and 20 radicular fragments. Radicular and coronal fragments were then randomly divided into 5 groups. Each group consisted of 8 specimens: 4 coronal and 4 radicular ones. A different adhesive system was used for each group following the manufacturer's directions. Each group underwent the same treatment: a thin layer of flowable composite was applied and then polymerized. Subsequently, a single 2 mm layer of microhybrid composite was added. The coronal and radicular portions were longitudinally cut to show the ground enamel/adhesive, unground enamel/adhesive and dentine/adhesive interfaces. Eighty specimens were obtained and prepared for SEM observation. Forty specimens with an adhesive/enamel interface and 40 with an adhesive/dentine interface. RESULTS: The interfacial exam frequently showed gaps between the substratum and the restoration. The final etching was generally satisfactory on ground enamel, while it was poor on unground enamel. Sometimes gaps were evident at the adhesive interface in dentin specimens. The tested adhesive systems produced a suitable hybrid layer and a lot of resin-tags were present. CONCLUSIONS: Self-etching adhesives showed an adequate adhesion to dentin. However, while they provided encouraging results on ground enamel they did not show to be dependable on unground enamel.


Subject(s)
Dental Cements , Dental Enamel , Dental Etching , Dentin , Dental Enamel/ultrastructure , Dentin/ultrastructure , Microscopy, Electron, Scanning , Surface Properties
8.
Minerva Stomatol ; 54(3): 139-51, 2005 Mar.
Article in English, Italian | MEDLINE | ID: mdl-15920446

ABSTRACT

AIM: The morphological characteristics of the filament structure, universally recognized as resin tags, in samples prepared using a new SEM methodology, are analyzed . METHODS: Ten non-carious, human third molars were cut transversally to obtain 10 dentinal surfaces. They were filled using an adhesive restorative technique. Subsequently, the samples were cut lengthwise to be SEM observed, and then randomly divided into 6 main groups according to the preparation modality of the section surface: Group A: EDTA; Group B: H(3)PO(4); Group C1: H(3)PO(4)+NaOCl; Group C2 H(3)PO(4)+NaOCl+H(2)O(2); Group D1: HCl+NaOCl; Group D2: HCl+NaOCl+H(2)O(2). RESULTS: The resin tags which originate from resin penetration and polymerization within the dentinal tubules are small conic-trunk shaped plugs that are a few microns long. The thinner extension of the resin tags is probably due to the persistence of the lamina limitans. CONCLUSIONS: A new method of specimen preparation for SEM visualization is proposed in order to effectively evaluate the penetration capacity of the adhesive in the dentinal substratum. In addition to the use of strong acids and bases, an agent capable of degrading the glycosaminoglycans was employed to completely remove the dentinal organic component.


Subject(s)
Composite Resins/analysis , Dental Etching , Dentin/ultrastructure , Microscopy, Electron, Scanning/methods , Molar, Third/ultrastructure , Specimen Handling/methods , Acid Etching, Dental , Artifacts , Collagen/ultrastructure , Dentin/drug effects , Edetic Acid/pharmacology , Formaldehyde , Humans , Hydrochloric Acid/pharmacology , Hydrogen Peroxide/pharmacology , In Vitro Techniques , Molar, Third/drug effects , Phosphoric Acids/pharmacology , Polymers , Preservation, Biological , Random Allocation , Sodium Hypochlorite/pharmacology
9.
Minerva Stomatol ; 53(10): 591-602, 2004 Oct.
Article in English, Italian | MEDLINE | ID: mdl-15531874

ABSTRACT

AIM: A morphological analysis is made of the titanium surface sandblasted using different sized microparticles, as well as an analysis of the adhesive interface after having layered the ceramic and resin on the same prepared surface. METHODS: A total of 14 titanium samples were prepared and randomly divided into 4 groups according to their different preparation methods. Group 1: control, no surface treatment. Group 2: 50 microm aluminium dioxide treatment. Group 3: 150 microm aluminium dioxide treatment. Group 4: Rocatec Plus system treatment. Samples of groups 2, 3, and 4 were subdivided into 2 groups: A) only sandblasted, B) sandblasted and ceramic (2B and 3B) or resin (4B) layered on top. The treated surface and the interface were then observed by scanning electrom microscope. RESULTS: Group 2 surface appeared irregular and rough; the interface with ceramic appeared discontinuous. Group 3 surface presented larger and deeper cavities where ceramic penetrated completely. Group 4 samples presented a rough surface covered by silicate particles and the interface between titanium and resin appeared regular and continuous. CONCLUSION: In order to guarantee an adequate interface, the 150 microm pretreated titanium surface seemed more suitable than the 50 microm one. The Rocatec Plus system was successful in obtaining an optimal layering with the resin due to its excellent quality.


Subject(s)
Adhesives , Ceramics , Composite Resins , Titanium , Materials Testing , Microscopy, Electron, Scanning , Random Allocation , Surface Properties
10.
Minerva Stomatol ; 52(4): 133-44, 2003 Apr.
Article in Italian | MEDLINE | ID: mdl-12874521

ABSTRACT

AIM: The purpose of this study was to compare 2 different techniques for the cementation of translucent fiber posts. The comparison was carried out by means of tensile bond strength testing and SEM evaluation of the interfaces morphology post/cement and cement/dentin. METHODS: Twenty upper central extracted incisors were first endodontically treated and then randomly divided into 2 groups of 10 samples each. Twenty translucent Endo Light-posts (RTD) were cemented following 2 different METHODS: In Group 1 Excite (Ivoclar Vivadent) and Tetric Flow (Ivoclar Vivadent) were applied and light-cured. In Group 2: All Bond 2 (Bisco) and RelyX ARC (3M) were applied, light-cured and then self-cured. A tensile bond strength test was carried out on 14 roots, 7 from each group. Subsequently, 2 roots were cut lengthwise and observed using a SEM. The remaining 6 roots (3 from each group) were cut into 5 transversal sections and observed using a SEM. The tensile force required to dislodge the cemented posts from the 7 roots of each group was recorded by means of a testing machine. RESULTS: Group 1 revealed a bonding strength which was slightly inferior to the bonding strength registered in Group 2. SEM evaluation showed a good quality of bond. Without taking into account the curing method used, the polymerization carried out by means of light curing seems to result in a better adaptation of cement. CONCLUSIONS: Self curing cement still represents the most reliable alternative, even if photo-curing cement might guarantee a most efficient stress distribution along the walls of the canal.


Subject(s)
Bisphenol A-Glycidyl Methacrylate , Cementation/methods , Composite Resins , Dental Bonding/methods , Materials Testing , Methacrylates , Polyethylene Glycols , Polymethacrylic Acids , Dental Restoration, Permanent , Humans , Light , Microscopy, Electron, Scanning
11.
Minerva Stomatol ; 52(4): 157-67, 2003 Apr.
Article in Italian | MEDLINE | ID: mdl-12874523

ABSTRACT

AIM: The purpose of the present study was to analyse bonding compatibility between photo- and self-polymerising composite resins ad two-step total-etch (one component) adhesive systems with a different activation method. METHODS: Thirty healthy extracted molars were cut transversally to obtain sixty flat dentin surfaces. The acid conditioned surfaces were bonded with Scotchbond 1 (3M), Excite (Vivadent) or Excite DSC (Vivadent). A cylinder of composite resin (3 mm diameter and 4 mm height) was constructed on each adhesive layer using photopolymerised Tetric Ceram (Vivadend) and dual Luxacore (DMG) but activated only chemically. The samples were subjected to the shear bond test. The fracture surfaces obtained were classified by type and site in the stereomicroscope. Twelve samples representing each group were further prepared for the SEM. RESULTS: The data obtained from the test, the microscopic investigation and statistical analysis (ANOVA and Bonferroni) seem to confirm the presence of a reduced bonding compatibility between one-component adhesive systems and self-polymerising composites. This incompatibility is evident for the adhesive Scotchbond 1 and limited for Excite, while it seems to be overcome by Excite DSC which appears to bond well with both Tetric Ceram and Luxacore. CONCLUSIONS: Adhesive-composite incompatibility seems to depend on the activation method of the composite as well as on that of the adhesive system. The chemical compatibility bet-ween these two materials is influenced not only by the chemical composition of the adhesive, but also by that of the composite.


Subject(s)
Acrylic Resins , Composite Resins , Dental Bonding/methods , Dental Cements , Dentin-Bonding Agents , Materials Testing , Methacrylates , Polyurethanes , Resin Cements , Shear Strength , Humans , Microscopy, Electron, Scanning
12.
Minerva Stomatol ; 51(7-8): 285-92, 2002.
Article in Italian | MEDLINE | ID: mdl-12434123

ABSTRACT

The situation with regard to current knowledge concerning dentinal sclerosis is examined. SEM and TEM examination of specimens of sclerotic dentin showed changes in diameter and tubular content leading to various degrees of obstruction of the lumen. There is agreement that this is due to the neo-apposition of peri-tubular dentin associated with intra-tubular deposition of crystals of Whitelockite, although the debate is still open on how such deposition may come about. Sclerotic casts are created in the tubules that may completely occlude the lumen or present a central cavity. In general these casts are surrounded by a thin fissure that has been variously interpreted. Many agree that sclerotic dentin has an increased mineral component, but without clarifying whether this is only a quantitative increase or whether it is also due to hyper-mineralisation of pre-existing dentin. An examination of the literature reveals numerous hypotheses surrounding the genesis of sclerotic dentin: some say it is due to passive phenomena of dissolution and precipitation whereas others suggest active involvement of the odontoblastic processes and the pulp. Since no studies have confirmed or confuted these theses, we may continue to think of dentinal sclerosis as a multifactorial event, due both to an increase in the thickness of peri-tubular dentin and to intra-tubular precipitation of calcium salts associated with mineralisation of the organic structures present in the lumen.


Subject(s)
Dentin/pathology , Calcium Phosphates/analysis , Crystallization , Dental Pulp/physiopathology , Dental Restoration Failure , Dental Restoration, Permanent , Dentin/chemistry , Dentin Solubility , Dentinogenesis , Humans , Microscopy, Electron , Models, Biological , Odontoblasts/pathology , Sclerosis
13.
Minerva Stomatol ; 43(10): 445-60, 1994 Oct.
Article in Italian | MEDLINE | ID: mdl-7700222

ABSTRACT

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.


Subject(s)
Dental Caries/pathology , Adolescent , Adult , Bicuspid/ultrastructure , Dentin/ultrastructure , Humans , Microscopy, Electron, Scanning/methods , Molar/ultrastructure
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