OBJECTIVES: The purpose of this study was to evaluate the effect of adhesive luting on the fracture resistance of zirconia compared to that of a composite resin and a lithium disilicate glass ceramic. MATERIALS AND METHODS: The specimens (dimension: 2 mm × 2 mm × 25 mm) of the composite resin, lithium disilicate glass ceramic, and yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) were prepared. These were then divided into nine groups: three non-luting groups, three non-adhesive luting groups, and three adhesive luting groups, for each restorative material. In the non-luting groups, specimens were placed on the bovine tooth without any luting agents. In the non-adhesive luting groups, only zinc phosphate cement was used for luting the specimen to the bovine tooth. In the adhesive luting groups, specimens were pretreated, and the adhesive luting procedure was performed using a self-adhesive resin cement. For all the groups, a flexural test was performed using universal testing machine, in which the fracture resistance was measured by recording the force at which the specimen was fractured. RESULTS: The fracture resistance after adhesive luting increased by approximately 29% in the case of the composite resin, 26% in the case of the lithium disilicate glass ceramic, and only 2% in the case of Y-TZP as compared to non-adhesive luting. CONCLUSIONS: The fracture resistance of Y-TZP did not increased significantly after adhesive luting as compared to that of the composite resin and the lithium disilicate glass ceramic.
Adhesives* ; Ceramics* ; Dental Cements ; Glass* ; Lithium* ; Resin Cements ; Tooth ; Zinc Phosphate Cement

PURPOSE: To evaluate the sealing performance of Hybrid Coat and its influence on the shear bond strength of five dentin surface cements. MATERIALS AND METHODS: Six premolars were pretreated to expose the dentin surface prior to the application of Hybrid Coat. The microscopic characteristics of the dentinal surfaces were examined with scanning electron microscopy (SEM). Then, 40 premolars were sectioned longitudinally, and 80 semi-sections were divided into a control group (untreated) and a study group (treated by Hybrid Coat). Alloy restoration was bonded to the teeth specimen using five different cements. Shear bond strength was measured by the universal testing machine. The fracture patterns and the adhesive interface were observed using astereomicroscope. RESULTS: SEM revealed that the lumens of dentinal tubules were completely occluded by Hybrid Coat. The Hybrid Coat significantly improved the shear bond strength of resin-modified glass ionomer cement (RMGIC) and resin cement (RC) but weakened the performance of zinc phosphate cement (ZPC), zinc polycarboxylate cement (ZPCC) and glass ionomer cement (GIC). CONCLUSION: Hybrid Coat is an effective dentinal tubule sealant, and therefore its combined use with resin or resin-modified glass ionomer cements can be applied for the prostheses attachment purpose.
Adhesives ; Alloys ; Bicuspid ; Dentin ; Glass Ionomer Cements ; In Vitro Techniques* ; Microscopy, Electron, Scanning ; Polycarboxylate Cement ; Prostheses and Implants ; Resin Cements ; Tooth ; Zinc Phosphate Cement

Cement-retained implant prosthesis has several advantages in the esthetic and occlusal aspects. However, the difficulty of the retrievability and the possibility of peri-implantitis induced by the cement excess would be a threatening factor to the implant prognosis. Peri-implantitis resulting from the remaining cement could occur later on to the patients with periodontitis history. Retention can be controlled by selecting the right cement type. Retention of the cement was the strongest in the resin cement, followed by resin modified glass ionomer cement, poIycarboxylate cement, zinc phosphate cement and glass ionomer cement. Retention of the provisional cement weakened after thermocycling. Other factors such as the abutment number, abutment alignment, height and taper of the abutment can also affect the total retention. To the success of the cement-retained prosthesis, it's important to select the right cement for the clinical purpose. The prosthesis should be fabricated in accordance with the biomechanical requirements. The prosthesis should be cemented with the techniques to reduce the excess cement as much as possible. In addition, the excess cement should be identified using the radiography and carefully removed.
Cementation* ; Glass Ionomer Cements ; Humans ; Peri-Implantitis ; Periodontitis ; Prognosis ; Prostheses and Implants* ; Radiography ; Resin Cements ; Zinc Phosphate Cement

PURPOSE: The purpose of this study was to evaluate the adaptation of lithium disilicate crowns fabricated by CAD-CAM (computer aided design-computer aided manufacturing) and heat-press technique to compare two different measurement methods in assessing fit of the ceramic crowns: micro CT and cross-section technique. MATERIALS AND METHODS: A prepared typodont mandibular molar for ceramic crown was duplicated and ten dies were produced by milling the PMMA (polymethylmethacrylate) resin. Ten vinyl polysiloxane impressions were made and stone casts were produced. Five dies were used for IPS e.max Press crowns with heat-press technique. The other five dies were used for IPS e.max CAD crowns with CAD-CAM technique. Ten lithium disilicate crowns were cemented on the resin dies using zinc phosphate cement with finger pressure. The marginal and internal fits in central buccolingual plane were evaluated using a micro CT. Then the specimens were embedded and cross-sectioned and the marginal and internal fits were measured using scanning electronic microscope. The two measurement methods and two manufacturing methods were compared using Mann-Whitney U test (SPSS 22.0). RESULTS: The marginal and internal fit values using micro CT and cross-section technique were similar, showing no significant differences. There were no significant differences in adaptation between lithium disilicate crowns fabricated with CAD-CAM and heat-press technique. CONCLUSION: Both micro CT and cross-section technique were acceptable methods in the evaluation of marginal and internal fit of lithium disilicate crown. There was no difference in adaptation between lithium disilicate crowns fabricated with CAD-CAM and heat-press technique except occlusal fit.
Ceramics ; Computer-Aided Design ; Crowns* ; Fingers ; Lithium* ; Molar ; Polymethyl Methacrylate ; Siloxanes ; Zinc Phosphate Cement

PURPOSE: The objective of this study was to evaluate the influence of various cement types on the stress distribution in monolithic zirconia crowns under maximum bite force using the finite element analysis. MATERIALS AND METHODS: The models of the prepared #46 crown (deep chamfer margin) were scanned and solid models composed of the monolithic zirconia crown, cement layer, and prepared tooth were produced using the computer-aided design technology and were subsequently translated into 3-dimensional finite element models. Four models were prepared according to different cement types (zinc phosphate, polycarboxylate, glass ionomer, and resin). A load of 700 N was applied vertically on the crowns (8 loading points). Maximum principal stress was determined. RESULTS: Zinc phosphate cement had a greater stress concentration in the cement layer, while polycarboxylate cement had a greater stress concentration on the distal surface of the monolithic zirconia crown and abutment tooth. Resin cement and glass ionomer cement showed similar patterns, but resin cement showed a lower stress distribution on the lingual and mesial surface of the cement layer. CONCLUSION: The test results indicate that the use of different luting agents that have various elastic moduli has an impact on the stress distribution of the monolithic zirconia crowns, cement layers, and abutment tooth. Resin cement is recommended for the luting agent of the monolithic zirconia crowns.
Bite Force ; Computer-Aided Design ; Crowns* ; Dental Cements ; Dental Stress Analysis ; Finite Element Analysis* ; Glass ; Glass Ionomer Cements ; Polycarboxylate Cement ; Resin Cements ; Tooth ; Zinc Phosphate Cement ; Zirconium

OBJECTIVES: To evaluate the effect of different ultrasonic tip designs on intraradicular post removal. MATERIALS AND METHODS: The crowns of forty human canine teeth were removed, and after biomechanical preparation and filling, the roots were embedded in acrylic resin blocks. The post spaces were made, and root canal molding was performed with self-cured acrylic resin. After casting (Cu-Al), the posts were cemented with zinc phosphate cement. The specimens were randomly separated into 4 groups (n = 10), as follows: G1 - no ultrasonic vibration (control); G2 - ultrasonic vibration using an elongated cylindrical-shaped and active rounded tip; G3 - ultrasonic vibration with a flattened convex and linear active tip; G4 - ultrasonic vibration with active semicircular tapered tip. Ultrasonic vibration was applied for 15 seconds on each post surface and tensile test was performed in a Universal Testing Machine (Instron 4444 - 1 mm/min). RESULTS: G4 presented the highest mean values, however, with no statistically significant difference in comparison to G3 (P > 0.05). G2 presented the lowest mean values with statistically significant difference to G3 and G4 (P < 0.05). CONCLUSIONS: Ultrasonic vibration with elongated cylindrical-shaped and active rounded tip was most effective in reducing force required for intraradicular post removal.
Crowns ; Cuspid ; Dental Pulp Cavity ; Fungi ; Humans ; Ultrasonics* ; Vibration ; Zinc Phosphate Cement

PURPOSE: The aim of this research was to establish the effect and variation in differing convergence angle and length of abutment on the retention of full veneer casted gold crown. MATERIALS AND METHODS: Two different length,5 mm and 10 mm in height with convergence angles of 5, 10, 15 and 25 degrees crowns were fabricated. Cementation was done using cements; zinc phosphate cement (Fleck's zinc phosphate cement), resin-modified glass ionomer cement (Vitremer) and resin cement (Panavia 21). These were tested for tensile force at the point of separation by using Instron Universal Testing Machine. Statistical analysis was done by SAS 6.04 package. RESULTS: In all cements the mean retention decreased with significant difference on increase of convergence angle (P<.05). Increase in every 5 degree-convergence angel the retention rate decreased with resin-modified glass ionomer cement of 15.9% and resin cement of 14.8%. With zinc phosphate cement, there was largest decreasing rate of mean retention of 25.5% between convergence angles from 5 degree to 10 degree. When the crown length increased from 5 mm to 10 mm, the retention increased with the significant difference in the same convergence angle and in all types of cement used (P<.05). CONCLUSION: The retention was strongly dependent on geometric factors of abutment. Much care is required in choosing cements for an optimal retention in abutments with different convergence angles and crown lengths.
Acrylic Resins ; Cementation ; Collodion ; Crowns ; Dental Cements ; Glass Ionomer Cements ; Phenothiazines ; Phosphates ; Resin Cements ; Retention (Psychology) ; Silicon Dioxide ; Zinc ; Zinc Compounds ; Zinc Phosphate Cement

PURPOSE: Many dentists use desensitizing agents to prevent hypersensitivity. This study compared and evaluated the effect of two desensitizing agents on the retention of cast crowns when cemented with various luting agents. MATERIALS AND METHODS: Ninety freshly extracted human molars were prepared with flat occlusal surface, 6 degree taper and approximately 4 mm axial length. The prepared specimens were divided into 3 groups and each group is further divided into 3 subgroups. Desensitizing agents used were GC Tooth Mousse and GLUMA(R) desensitizer. Cementing agents used were zinc phosphate, glass ionomer and resin modified glass ionomer cement. Individual crowns with loop were made from base metal alloy. Desensitizing agents were applied before cementation of crowns except for control group. Under tensional force the crowns were removed using an automated universal testing machine. Statistical analysis included one-way ANOVA followed by Turkey-Kramer post hoc test at a preset alpha of 0.05. RESULTS: Resin modified glass ionomer cement exhibited the highest retentive strength and all dentin treatments resulted in significantly different retentive values (In Kg.): GLUMA (49.02 +/- 3.32) > Control (48.61 +/- 3.54) > Tooth mousse (48.34 +/- 2.94). Retentive strength for glass ionomer cement were GLUMA (41.14 +/- 2.42) > Tooth mousse (40.32 +/- 3.89) > Control (39.09 +/- 2.80). For zinc phosphate cement the retentive strength were lowest GLUMA (27.92 +/- 3.20) > Control (27.69 +/- 3.39) > Tooth mousse (25.27 +/- 4.60). CONCLUSION: The use of GLUMA(R) desensitizer has no effect on crown retention. GC Tooth Mousse does not affect the retentive ability of glass ionomer and resin modified glass ionomer cement, but it decreases the retentive ability of zinc phosphate cement.
Acrylic Resins ; Alloys ; Caseins ; Cementation ; Collodion ; Crowns ; Dental Cements ; Dentin ; Dentin Sensitivity ; Dentists ; Glass ; Glass Ionomer Cements ; Glutaral ; Humans ; Hypersensitivity ; Molar ; Phosphates ; Polymethacrylic Acids ; Retention (Psychology) ; Silicon Dioxide ; Tooth ; Zinc ; Zinc Compounds ; Zinc Phosphate Cement

PURPOSE: To report a case of bilateral serous retinal detachment associated with Alport's syndrome that resolved following intensive blood pressure control and electrolyte imbalance correction. CASE SUMMARY: A 50-year-old male patient presented with bilateral lenticonus and bilateral serous retinal detachment. Bilateral serous retinal detachment with retinal flecks characteristic of Alport's syndrome appeared along with the development of chronic renal failure and hypertension. The following kidney biopsy revealed Alport's syndrome. After 14 days, the serous detachment resolved and vision recovered following intensive blood pressure control and electrolyte imbalance correction fundus and FA results were nearly normal. CONCLUSIONS: In this case, bilateral serous retinal detachment in Alport's syndrome resolved with intensive blood pressure control and electrolyte imbalance correction. To the author's knowledge, this is the first case in South Korea with documentation of the onset and resolution of bilateral serous retinal detachment in Alport's syndrome.
Biopsy ; Blood Pressure ; Humans ; Hypertension ; Kidney ; Kidney Failure, Chronic ; Male ; Middle Aged ; Nephritis, Hereditary ; Republic of Korea ; Retinal Detachment ; Retinaldehyde ; Vision, Ocular ; Zinc Phosphate Cement

STATEMENT OF PROBLEM: Over the years, resin-bonded fixed partial dentures (RBFPDs) have gone through substantial development and refinement. Several studies examined the biomechanics of tooth preparation and framework design in relation to the success rate of RBFPDs and considered retention and resistance form essential for increase of clinical retention. However, these criteria required preparations to be more invasive, which violates not only the original intentions of the RBFPD, but may also have an adverse effect on retention due to loss of enamel, an important factor in bonding. PURPOSE: The object of this in vitro study was to compare the dislodgement resistance of the new types of RBFPDs, the conventional three-unit fixed partial denture, and conventional design of RBFPD (Maryland bridge). MATERIAL AND METHODS: Fifty resin mandibular left second premolars and second molars were prepared on dentiforms, according to the RBFPD design. After model fabrication (five group, n = 10), prostheses were fabricated and cemented with zinc phosphate cement. After cementation, the specimens were subjected to tensile loading at a cross head speed of 4 mm/min in a universal testing machine. The separation load was recorded and analyzed statistically using one-way analysis of variance followed by Duncan's multiple range test. RESULTS: Group V, the pin-retained RBFPDs, had the highest mean dislodgement resistance, whereas specimens of group II, the conventional RBFPDs, exhibited a significantly lower mean dislodgement resistance compared to the other 4 groups (P < .05). There were no significant differences between group I, III, and IV in terms of dislodgement resistance (P > .05). Group V had the highest mean MPa (N/mm2) (P < .05). There was no significant difference between groups I, II, III and IV (P > .05). CONCLUSION: Within the limits of the design of this in vitro study, it was concluded that: 1. The modified RBFPDs which utilizes the original tooth undercuts and requires no tooth preparation, compared with the conventional design of RBFPDs, has significantly high dislodgement resistance (P < .05). 2. The modified RBFPDs which utilizes the original tooth undercuts and requires minimal tooth preparation, compared with the conventional FPDs, has significantly no difference in retention and dislodgement resistance)(P > .05). 3. The pin-retained FPDs showed a high dislodgement resistance compared to the conventional three-unit FPDs (P < .05).
Bicuspid ; Biomechanics ; Cementation ; Collodion ; Dental Enamel ; Denture, Partial, Fixed ; Head ; Intention ; Molar ; Phosphates ; Prostheses and Implants ; Retention (Psychology) ; Tooth ; Tooth Preparation ; Zinc Compounds ; Zinc Phosphate Cement