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Biomedical subjects

M C Cagidiaco

Publications and source records attributed to M C Cagidiaco.

At least 19 recordsLinked to original sources
PubMed2001

Bonding of all-porcelain crowns: structural characteristics of the substrate.

OBJECTIVES: The aim of this in vitro study was to evaluate the morphology of dentin in teeth prepared for single-unit all-porcelain crowns (SUAPC) in terms of tubule orientation, density and increase in surface area after etching. METHODS: Twenty anterior and 20 posterior teeth from adults were prepared 1mm below the cemento-enamel junction (CEJ) for SUAPC. The samples were divided into groups based on type of tooth (anterior or posterior) and bonding system employed. The teeth were processed for evaluation of morphology of the substrate, hybrid layer thickness and resin tag formation. The observations were subdivided according to location in the preparation and tubule density was calculated. RESULTS: The observations revealed the variability in tubule density and orientation in different areas within any one preparation. The morphology of the cervical margin was less predictable with the presence of cementum and an ill-defined cemento-dentinal junction. Statistically significant differences in the density of tubules were found depending on location. Groups 2, 3, 5 and 6 samples showed that the hybrid layer thickness and resin tag morphology depended on the density and direction of tubules. In those sectors with parallel and oblique tubule orientation and with a low density of tubules, the hybrid layer was significantly thinner than in areas with cross-sectioned tubules. SIGNIFICANCE: The cementum and the peripheral intertubular dentin surface area are likely to be responsible for the bond strength after acid etching of crown preparations, but not all areas exhibited equal responses to etching. In particular, the bonding substrate at the gingival margins may contribute little in terms of micromechanical retention.

Acid Etching, Dental↗
PubMed2000

Bonding to root canal: structural characteristics of the substrate.

PURPOSE: To evaluate in vitro the dentin morphology in root canals in terms of tubule orientation, density and increase in surface area after etching. MATERIALS AND METHODS: Thirty anterior teeth were divided in 3 groups at random: the samples of Group 1 were used to study tubular morphology in SEM. Groups 2 and 3 samples were etched with 32% phosphoric acid. The teeth in Group 2 were examined by SEM without further treatment. The samples in Group 3 were treated with a bonding system and fiber posts were luted into the canal. These teeth were then processed for evaluation of hybrid layer formation and resin tags in dentin tubules. The observations were made according to location in the root dentin, tubule density was estimated, and the increase in area available for bonding after etching was calculated. RESULTS: The observations revealed variability in tubule density and orientation within different areas of any one sample. Statistically significant differences in the density of tubules were found depending on location. The dentin surface area available for bonding increased by 202% after etching in the cervical third, 156% in the middle third, and 113% in the apical third of the root dentin. Group 3 samples showed that the thickness of the hybrid layer depended on the density of tubules. In the sectors with a low density of tubules, the hybrid layer was significantly thinner than in areas with a higher density of tubules. The increase in dentin surface area might be responsible for the enhanced bond strength after acid etching, but not all areas exhibited equal responses to etching.

Acid Etching, Dental↗
PubMed1999

Clinical evaluation of a one-bottle bonding system for desensitizing exposed roots.

PURPOSE: To evaluate the effectiveness of a one-bottle adhesive system as a desensitizing treatment, with or without a prior phosphoric acid-etch step. MATERIALS AND METHODS: Two different clinical procedures using a one-bottle adhesive bonding system were tested for its efficacy on desensitizing exposed roots. Thirty subjects with a history of dentin hypersensitivity were selected and 60 exposed sensitive teeth were divided into two groups (n = 30). In Group 1 samples, Scotchbond 1 bonding system (Single Bond in USA) was applied without a prior acid-etching, while in those of Group 2, the exposed sensitive roots were acid-etched with 35% phosphoric acid for 15 seconds, prior to application of bonding agents. The sensitivity was evaluated at 0, 1, 2, 4 weeks and 3 months using cold air blast stimuli, and recorded using a visual-analogue scale. The scores were analyzed as non-parametric data by means of the Mann-Whitney and Sign tests. Five samples from each group were randomly selected in order to make scanning electron microscope observations of the sensitive dentin surfaces at baseline and at each recall using the replica technique. RESULTS: At baseline, after both desensitizing procedures all the patients reported distinct reductions in dentin sensitivity. At 1- and 2-week recalls, 20 teeth of Group 1 and 17 teeth in Group 2 exhibited a return of sensitivity, and in five teeth in each group, the sensitivity score was between 5-8. During the first recall (1-2 weeks), the sensitive teeth were retreated and showed an immediate reduction of sensitivity. At the 1-month recall, eight teeth in Group 1 and four teeth in Group 2 showed a return of some sensitivity, and in six teeth in Group 1 and in three teeth in Group 2, old amalgam restorations were replaced and this procedure almost completely resolved the sensitivity. At the 3-month recall, only five teeth from each group showed residual mild sensitivity (score 1-2). For both Groups 1 and 2 there was a statistically significant (P < 0.0005) reduction in sensitivity levels between the baseline pain scores and immediately after treatment, and between the first recall pre-treatment pain scores and the last recall pain scores. Overall, the two methods of treatment demonstrated a general decrease in sensitivity in both groups over the 3-month study period, adequately solving the clinical and patients' perception of the discomfort of sensitivity. The SEM observations of the replicas showed a progressive loss of the adhesive resin from the treated surfaces. This fact was more evident in the non-etched samples (Group 2) than in those in Group 1. The results of this study showed that exposed root dentin sealed with Scotchbond 1, with or without prior acid-etching, did not show spontaneous sensitivity after 3 months.

Acid Etching, Dental↗
PubMed1999

Influence of tissue characteristics at margins on leakage of Class II indirect porcelain restorations.

PURPOSE: To evaluate the sealing ability of Class II porcelain inlays with margins placed in cementum-dentin and enamel, luted by two new different cementing materials. MATERIALS AND METHODS: Thirty extracted molars, free from caries and restorations, were selected. The sample cavities were prepared in a standardized manner and then were divided in three groups (n = 10) at random. Group 1: The cervical margin was located 1 mm below the CEJ and the inlays were luted with EBS Multi (Espe) bonding system in combination with Compolute 1.0 Aplicap (CLA 1.0, Espe) experimental resin cement. Group 2: The cervical margin was placed 1 mm below the CEJ and Syntac bonding system (Vivadent) and Variolink II resin cement (Vivadent) were used. Group 3: The cervical margin was placed 0.5 mm above the CEJ and the same materials selected for Group 1 were used. IPS-Empress (Ivoclar) inlays were made following manufacturer's instructions. After luting procedures and 2500 thermal cycles (5 degrees and 55 degrees C), the samples were processed and evaluated for marginal leakage at cervical and occlusal site. Samples of Group 3 were first sectioned in the center of the restorations as in Group 1 and 2 and scored (Group 3A) and then two other cuts were made along the buccal and lingual areas (Group 3B) and also scored. After scoring dye penetration of Group 1 and 2 samples, half of the sections were randomly selected to evaluate: (1) resin cement thickness, (2) Hybrid layer formation at the interface between adhesive material and dental substrate and (3) to observe the morphology of the Class II cavity margins. The leakage data were statistically evaluated with the Mann-Whitney U test (P < 0.5). RESULTS: Statistically significant differences were found between Groups 3A and 3B at the occlusal site, and not at the cervical site. Samples of Group 1 showed a cement thickness of 92 microns, and 68 microns in Group 2. Hybrid layer and resin tag formation was evident in Group 1. In Group 2 samples, the hybrid layer formation was less evident and thinner than in Group 1. At cervical margins, an outer layer, not identifiable as sound dentin, of 200-300 microns thick, was noted. This layer was present in all three groups between outer margin and sound dentin. The margins located both cervically and axially in enamel mainly showed prisms cut along their long axis and a low level of structured etch pattern.

Aged↗
PubMed1997

Short-term assessment of leakage of Class V composite restorations placed in vivo.

The purpose of this study was to investigate the effectiveness of two dentin bonding systems, one of which was also in combination with a self-curing resin, when applied in V-shaped circular cavities cut in anterior teeth crossing the cementum-enamel junction. Twenty-seven teeth scheduled for extraction for periodontal reasons were treated in vivo. The sample teeth were divided at random into three groups. Group 1 was treated with All Bond 2 (AB2) + Z-100 composite, group 2 with Scotchbond Multipurpose Plus (SMPP) + Z-100, and group 3 with AB2 in conjunction with Bisfil 2B as liner and Z-100. The in vivo restored teeth were extracted after 2-3 months of clinical service. They were then immersed in a dye solution for 24 h, sectioned, and scored for marginal leakage. Analysis of variance revealed no significant differences between the three groups both at cervical and incisal sites. The enamel sites were free from any leakage. Only two cervical sites of groups 1 and 2 and one of group 3 showed a score 1 for leakage. The results of the short-term clinical performance of the three systems were promising.

Analysis of Variance↗
PubMed1997

Resistance of cementum in Class II and V cavities to penetration by an adhesive system.

OBJECTIVES: As the cervical margin located in cementum-dentin is still the most unpredictable area of an adhesive resin restoration, the aim of this investigation was to evaluate the morphology of the cementum layer at the cervical margins of Class V and Class II cavities and the impregnability of this layer to resin bonding systems. METHODS: Three different types of in vitro investigations of the cervical margins were performed by scanning electron microscopy: 1) direct anatomical observation of conditioned cavities; 2) observation of resin replicas; and 3) observation of resin infiltration. During direct observation, the presence of opened tubules was evaluated; in the resin replicas, the presence of resin tags and their density were observed; in the observation of resin infiltration, the presence of an acid-resistant interdiffusion was investigated. RESULTS: From direct observation, cut tubules were seen 200 microns from the cervical margin. After treatment with a dentin bonding system, the outer layer was infiltrated by the resin. In the resin replica, the presence of resin tags was detectable 150-200 microns from the margin. In Class II samples, the presence of an outer layer at the cervical margin, which could not be identified as bulk dentin or cementum, was clearly detectable by both direct and indirect observation. In the Class V samples, the border between this layer and bulk dentin was less evident. SIGNIFICANCE: The presence of a cementum layer of approximately 150-200 microns at the cervical margins of cavities may pose a serious clinical problem for reliable bonding. Although in the present study the observation of a zone of resin-impregnated cementum may confirm the improvement obtained with the last generation of hybridizing dentin bonding systems, the effectiveness of the bond is still unclear.

Composite Resins↗
PubMed1997

Mapping of tubule and intertubule surface areas available for bonding in Class V and Class II preparations.

OBJECTIVES AND METHODS: The aim of this in vitro study was to evaluate the morphology of dentine in Class V and the Class II preparation walls in terms of tubule orientation, density and increase in surface area after conditioning. Six circular V-shaped preparations were cut at the cementum-enamel junction (CEJ) of anterior teeth and six Class II cavities with the cervical margin 1 mm below the CEJ were prepared in posterior teeth. The preparations were conditioned with 10% maleic acid. The samples were directly studied by SEM. The observations were organized according to location in the preparation, tubule density was counted and the increase in area available for bonding after acid etching was calculated. RESULTS: Dentine morphology of Class V and Class II preparation walls was mostly regular according to predictable patterns. Between the tubules, along the walls of the cavity, the etched dentine surface exhibited a porous network of collagen fibers. More than 50% of Class V and Class II cavity surface presented oblique or parallel tubule orientation with respect to the cut surface. Because of the presence of a structureless cementum layer. the morphology of the cervical area turned out to be less predictable. The tubule density varied considerably in different regions of the preparations. The intertubular dentine surface area increased after conditioning in Class V preparations from 20.9% to 50.3% on the walls where tubules were cut parallel to their long axis, and from 5.8% to 47.8% where tubules were cut perpendicularly. These same values for Class II preparations ranged from 0.6% to 46.4% on the walls where tubules were cut parallel to their long axis, and 29.8% of the tubules were cut perpendicularly. CONCLUSIONS: Based on this morphological investigation, the increase in intertubular dentine surface area might very well be responsible for the enhanced bond strength after acid etching of dentine, but not all areas exhibited equal responses to etching. In particular, the bonding substrate at the gingival margins may contribute little in terms of micromechanical retention.

Acid Etching, Dental↗
PubMed1996

Shear bond strength of four dentinal adhesives applied in vivo and in vitro.

OBJECTIVES: The purpose of this study was to determine whether dentine bonding performed under clinical conditions is as reliable as laboratory bonding. METHODS: Freshly cut dentine was used in vivo or in vitro as a substrate for the bonding of various adhesive systems. Bond strength was measured in shear loading. RESULTS: Clearfil Liner Bond, Optibond and All Bond 2 showed better results when applied in vivo than in vitro. Scotchbond Multipurpose showed the opposite effect but the bond strength was, for both conditions, superior to the other three products. Only All Bond 2 presented statistically significant differences in bond strength between in vivo and in vitro applied bonding. CONCLUSIONS: The results indicate that, with the new hydrophilic dentine bonding systems, in vitro application does not lead to substantially different results when compared with, in vivo application.

Adhesives↗
PubMed1996

Tissue management with a new gingival retraction material: a preliminary clinical report.

A new retraction material (Merocel) was evaluated in a clinical trial with 10 selected abutments. Each selected abutment required an anterior single unit. A comparison of probing attachment level, bleeding on probing, and plaque index demonstrated highly successful periodontal maintenance. The main advantage of Merocel retraction material is that it is capable of innocuously expanding the gingival sulcus. This preliminary study suggested that a Merocel strip was a predictable retraction material in conjunction with impression procedures. The material was also evaluated by scanning electron microscopy and demonstrated promise in this investigation. The Merocel strip shows potential for other applications, but limitations of this material indicated that evolution of atraumatic gingival retraction should continue.

Adult↗
PubMed1996

Dentin contamination protection after mechanical preparation for veneering.

PURPOSE: To evaluate in vivo the efficacy in preventing post-operative sensitivity and bacterial invasion of primed dentin that was left unprotected for 4 days after laminate veneer preparation. MATERIALS AND METHODS: Twelve vital, periodontically involved anterior teeth were prepared for experimental laminate veneers and divided into three groups: (1) Control group, in which the prepared surfaces were left unprotected after preparation; (2) Prepared dentin surfaces were cleaned with Tubulicid Red Label and covered with Tubulitec Primer; (3) All-Bond 2 Primer was applied to the prepared dentin surface. Post-operative sensitivity was evaluated immediately and a second appointment, 4 days later. The teeth were then extracted and examined by SEM. RESULTS: The application of a primer (Groups 2 and 3) prevented all sensitivity. After 4 days, the teeth in Group 1 were still sensitive to air blasts. Bacterial penetration into the unprotected tubules was observed in Group 1, but not in Groups 2 and 3.

Adult↗
PubMed1996

Dentin infiltration by three adhesive systems in clinical and laboratory conditions.

PURPOSE: To evaluate in vivo and in vitro the formation of hybrid layer, resin tags and adhesive lateral branches, by use of three different enamel dentin bonding systems. MATERIALS AND METHODS: The dentin adhesives were tested on flat dentin preparations made on buccal surfaces of vital, periodontally compromised teeth. The samples were randomly divided in four groups: Group 1: Prime & Bond 2.0; Group 2: Scotchbond Multi-Purpose Plus; Group 3: Clearfil Liner Bond 2 (the self-etching primer was applied for 30 seconds on the enamel and dentin); Group 4: Clearfil Liner Bond 2 (the self-etching primer was applied for 60 seconds on the enamel and dentin). The sample teeth were extracted immediately after the bonding was cured. The same procedure described for the in vivo samples was performed in vitro on extracted molars. All the samples were split-fractured along their long axis. Half of the samples were used to visualize the hybrid layer and the other half to observe the morphology of resin tags by use of scanning electron microscopy. RESULTS: All the tested products formed a hybrid layer, both in vivo and in vitro. In many areas of the samples of Groups 1, 2 and 4, characteristic reverse cone-shaped tags with their corresponding adhesive lateral branches were evident. In contrast to this, resin tags found in samples of Group 3 were narrower at the tubule orifices, and adhesive lateral branches were scarce. The length of the resin tags observed in the samples of Groups 1 and 2 were longer than those found in Groups 3 and 4. The morphology of the hybrid layer of the in vivo samples was similar to that of the in vitro samples.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1994

Micromorphologic relationship between resin and dentin in Class II restorations: an in vivo and in vitro investigation by scanning electron microscopy.

The wetting property of dentinal bonding systems may play an important role in the mechanism of adhesion to dentin. Some studies have observed that tags penetrate 100 microns or more in nonvital teeth and less than 10 microns in vital teeth. This investigation was designed to evaluate the micromorphologic relationship between in vivo and in vitro dentin after application of two new dentinal bonding systems in Class II restorations. Class II cavities were restored in vitro and in vivo with Gluma 2000 adhesive and Pekafill hybrid resin or Scotchbond Multi-purpose adhesive and Z100 composite resin. After dissolution of dental structures, the restorations were observed with a scanning electron microscope. No morphologic differences were found between in vivo and in vitro specimens with either of the new dentinal adhesive systems tested. Short resin tags were often found in vivo, particularly at the cavity walls. Only a few areas in vivo had deep resin tags (longer than 100 microns) and these were always at the cavity floor.

Adhesiveness↗
PubMed1994

Traumatic injuries to permanent incisors: a case report.

A case report involving traumatized maxillary incisors is presented. The right central and lateral incisors were avulsed by direct trauma and were not found. The left central incisor was luxated and the left lateral incisor was fractured at the coronal portion. Placement of implant fixtures was selected as treatment to prevent resorption of alveolar bone and to maintain the integrity of intact adjacent teeth. The right incisors were replaced with two osseointegrated implants. The left central incisor was endodontically treated and a cast post and core was bonded into the root canal. All three of these teeth were restored with porcelain-fused-to-metal crowns. A composite resin restoration was placed on the left lateral incisor. The esthetic and functional results were satisfactory.

Accidents, Traffic↗
PubMed1993

Preliminary report of an experimental design for in vivo testing of bonded restorations applied to a new enamel-dentinal bonding agent.

Because of inconsistency often found between in vitro testing and in vivo performance, a new restorative bonding system was evaluated by the placement of restorations in vivo in teeth to be extracted. The microleakage was determined following extraction after 3 months of clinical service. In each of the sample teeth, two restorations were placed on the labial surface, one in the middle of the enamel portion and the other extending over the cementoenamel portion. The results of this pilot study indicated that bonding to conditioned enamel with the new adhesive material is effective, and bonding to conditioned dentin appears to be clinically adequate.

Acid Etching, Dental↗
PubMed1992

Cement thickness and microleakage under metal-ceramic restorations with a facial butted margin: an in vivo investigation.

Ten metal-ceramic restorations with buccal porcelain butt margins and palatal metal beveled margins were fabricated for periodontally hopeless teeth. After cementation, the experimental crowns remained in the oral environment for 3 to 6 months; the teeth were then extracted and used for microscopic and microleakage evaluation. All ten crowns showed at least a small amount of microleakage, but adaptation of beveled margins proved to be superior to that of shoulder porcelain margins.

Cementation↗
PubMed1989

Evaluation of a chemical etching solution for nickel-chromium-beryllium and chromium-cobalt alloys.

Two chemical etching solutions were capable of providing micromechanical retention in two nickel-chromium-beryllium alloys and in a chromium-cobalt alloy. A resin matrix was used to verify the quality of etching on the metal surfaces. The chemical etching solutions created high microretentive surfaces in nickel-chromium-beryllium alloy but the chromium-cobalt alloy surfaces after etching were less retentive. Improved chemical etching technique should encourage expanded use of the resin-bonded retainers.

Acid Etching, Dental↗