• Korean Journal of Dental Materials
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• v.45 no.4
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• pp.301-310
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• 2018

The purpose of this study is to evaluate the compatibility of universal adhesives with two dual-cured resin cements. Eighty human molars were divided into eight groups. Tooth was embedded in self-curing acrylic resin and sectioned horizontally to exposure dentine surface. After polishing with 600-grit SiC paper, adhesives were applied. All-Bond Universal (Bisco), G-premio bond (GC), Scotch-bond universal (3M ESPE), Scotch-bond Multipurpose (3M ESPE) were used in this study. Calibra (Dentsply) as a conventional dual-curing resin cement and RelyX Ultimate (3M ESPE) as an amine free resin cement were used. The adhesives and the cements were applied according to the manufacturer's instructions. Final specimens were cylinder (diameter 2mm, height 3mm) shape. After storing in distilled water at $37^{\circ}C$ for 7 days the shear bond strength (SBS) test was performed. There was no significant difference in shear bond strength between the adhesives when RelyX Ultimate was used (p>0.05). However, when Calibra used with Scotch-bond Multipurpose and All-Bond Universal were used, statistically higher SBS was observed, as compared to the groups which Calibra cements with G-premio bond and Scotch-bond universal adhesive (p<0.05) were used. Within the limitations of this study, RelyX Ultimate resin cement was compatible with universal adhesives of various pH. All-Bond Universal adhesive was compatible with a resin cement containing the tertiary amine.

• Restorative Dentistry and Endodontics
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• v.39 no.1
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• pp.39-44
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• 2014

Objectives: The purpose of this study was to evaluate in vitro cytotoxicity of the pozzolan cement and other root-end filling materials using human periodontal ligament cell. Materials and Methods: Endocem (Maruchi), white ProRoot MTA (Dentsply), white Angelus MTA (Angelus), and Super EBA (Bosworth Co.) were tested after set completely in an incubator at $37^{\circ}C$ for 7 days, Endocem was tested in two ways: 1) immediately after mixing (fresh specimens) and 2) after setting completely like other experimental materials. The methods for assessment included light microscopic examination, cell counting and WST-1 assay on human periodontal ligament cell. Results: In the results of microscopic examination and cell counting, Super EBA showed significantly lower viable cell than any other groups (p < 0.05). As the results of WST-1 assay, compared with untreated control group, there was no significant cell viability of the Endocem group. However, the fresh mixed Endocem group had significantly less cell viability. The cells exposed to ProRoot MTA and Angelus MTA showed the highest viability, whereas the cells exposed to Super EBA displayed the lowest viability (p < 0.05). Conclusions: The cytotoxicity of the pozzolan cement (Endocem) was comparable with ProRoot MTA and Angelus MTA. Considering the difficult manipulation and long setting time of ProRoot MTA and Angelus MTA, Endocem can be used as the alternative of retrofilling material.

• Journal of Periodontal and Implant Science
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• v.49 no.1
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• pp.39-46
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• 2019

Purpose: This study aimed to evaluate the effects of i) the extent of peri-implant bone defects and ii) the application of bone cement on implant stability with respect to the measurement direction. Methods: In 10 bovine rib bones, 4 implant osteotomies with peri-implant bone defects of various widths were prepared: i) no defect (D0), ii) a 2-mm-wide defect (D2), iii) a 4-mm-wide defect (D4), and iv) a 8-mm-wide defect (D8). The height of all defects was 10 mm. Implant stability quotient (ISQ) values and Periotest values (PTVs) were measured after implant placement and bone cement application. Results: With increasing defect width, decreased ISQs and increased PTVs were observed. Statistically significant differences were found between groups D0 and D8, D0 and D4, and D2 and D8. Prior to bone cement application, inconsistent PTVs were found in group D8 depending on the measurement direction. Bone cement increased the implant stability. Conclusion: Peri-implant bone deficits measuring around 50% of the implant surface compromised implant stability. Clinically, PTVs should be cautiously interpreted in implants with large peri-implant defects due to inconsistent recordings with respect to the measurement direction.

• The Journal of the Korean dental association
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• v.51 no.11
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• pp.595-603
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• 2013

The requirements for the successful treatment of all-ceramic restorations are not so different from the ones of conventional restorations. "The provisional restoration followed by an adequate tooth reduction and the accurately fitting prostheses with corresponding to final impression" can be the examples of them. Nevertheless, the one which all-ceramic restorations are distinguished from conventional restorations is the additional procedure of so called "bonding". In addition to the application of resin cement between "inner surface of restoration and outer surface of abutment", bonding technology can be also applied to the treatment process of "Post and Core" in particular if the abutments are non-vital teeth. Core build-up for all-ceramic crown is conducted with fiber post and tooth colored composite by considering the properties of the restorations transmitting light. We know well that a vital abutment is easier than a non-vital one to get the targeted goals for clinical success in connection with esthetics and structure. The creation of "Post and Core" with bonding technique is a decisive factor for a long-term success if the abutment is non-vital tooth with dentinal collapse. I would like to share my clinical experience about "post & core build-up and all-ceramic restoration bonding" out of several success strategies of all-ceramic crown with this presentation.

• The Journal of Advanced Prosthodontics
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• v.9 no.4
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• pp.244-251
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• 2017

PURPOSE. The purpose of this study was to determine fracture resistance and failure modes of three-unit fixed dental prostheses (FDPs) made of lithium disilicate pressed on zirconia (LZ), monolithic lithium disilicate (ML), and monolithic zirconia (MZ). MATERIALS AND METHODS. Co-Cr alloy three-unit metal FDPs model with maxillary first premolar and first molar abutments was fabricated. Three different FDPs groups, LZ, ML, and MZ, were prepared (n = 5 per group). The three-unit FDPs designs were identical for all specimens and cemented with resin cement on the prepared metal model. The region of pontic in FDPs was given 50,000 times of cyclic preloading at 2 Hz via dental chewing simulator and received a static load until fracture with universal testing machine fixed at $10^{\circ}$. The fracture resistance and mode of failure were recorded. Statistical analyses were performed using the Kruskal-Wallis test and Mann-Whitney U test with Bonferroni's correction (${\alpha}=0.05/3=0.017$). RESULTS. A significant difference in fracture resistance was found between LZ ($4943.87{\pm}1243.70N$) and ML ($2872.61{\pm}658.78N$) groups, as well as between ML and MZ ($4948.02{\pm}974.51N$) groups (P<.05), but no significant difference was found between LZ and MZ groups (P>.05). With regard to fracture pattern, there were three cases of veneer chipping and two interfacial fractures in LZ group, and complete fracture was observed in all the specimens of ML and MZ groups. CONCLUSION. Compared to monolithic lithium disilicate FDPs, monolithic zirconia FDPs and lithium disilicate glass ceramics pressed on zirconia-based FDPs showed superior fracture resistance while they manifested comparable fracture resistances.

• The Journal of Advanced Prosthodontics
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• v.8 no.3
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• pp.194-200
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• 2016

PURPOSE. The prospective follow-up aimed to assess the performance of lithium disilicate crowns and clinical reasons of adverse events compromising survival and quality. MATERIALS AND METHODS. 58 patients were treated with 375 heat-pressed monolithic crowns, which were bonded with resin cement. Annual recalls up to five years included a complete dental examination as well as quality assessment using CDA-criteria. Any need for clinical intervention led to higher complication rate and any failure compromised the survival rate. Kaplan-Meier-method was applied to all crowns and a dataset containing one randomly selected crown from each patient. RESULTS. Due to drop-outs, 45 patients (31 females, 14 males) with the average age of 43 years (range = 17-73) who had 327 crowns (176 anterior, 151 posterior; 203 upper jaw, 124 lower jaw) were observed and evaluated for between 4 and 51 months (median = 28). Observation revealed 4 chippings, 3 losses of retention, 3 fractures, 3 secondary caries, 1 endodontic problem, and 1 tooth fracture. Four crowns had to be removed. Survival and complication rate was estimated 98.2% and 5.4% at 24 months, and 96.8% and 7.1% at 48 months. The complication rate was significantly higher for root canal treated teeth (12%, P<.01) at 24 months. At the last observation, over 90% of all crowns showed excellent ratings (CDA-rating Alfa) for color, marginal fit, and caries. CONCLUSION. Heat pressed lithium disilicate crowns showed an excellent performance. Besides a careful luting, dentists should be aware of patients' biological prerequisites (grade of caries, oral hygiene) to reach full success with these crowns.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.4
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• pp.423-430
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• 2016

The implant prosthesis can be divided into the screw retained prosthesis and cement retained prosthesis. Each type has advantages as well as disadvantages which is unfavorable to maintain the implants. To overcome these drawbacks, T-screw system was developed. T-screw system which utilizes a lingual direction of the screw to retain the implant prosthesis, has advantages of retrievability of the prosthesis, passive fit, and possibility to form esthetic and functional occlusal surface. The prior prosthesis which utilized horizontal screws had difficulty in fabrication especially in the case of multiple units, and also limited use with all-ceramic prosthesis. In this case, fabricating the implant prosthesis by using the T-screw system showed superior results in easy maintenance, esthetics, and also functions. In addition, we are to report the method of using the T-screw system in implant prosthesis, such as multiple units of implant prosthesis and all ceramic prosthesis.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.1
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• pp.82-86
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• 2001

The aim of this study was to investigate the level of radiopacity of esthetic dental restorative materials and determine the optimum level of radiopacity in pediatric dentistry. Disks of 8 dental restorative material groups as the experimental group, 7mm in diameter and 2mm thick, were radiographed with intact human deciduous teeth and aluminum stepwedge standard. Radiopacity was evaluated with an image analysis program following the digitization of the radiographs using a flatbed scanner with transparency unit. All materials and tooth structure also the significant difference except FP, VB, VM. For the radiopacity of esthetic restorative dental materials to exceed that of enamel, it should be greater than 1.7mm of equivalent thickness of aluminum.

• Journal of Periodontal and Implant Science
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• v.43 no.2
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• pp.58-63
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• 2013

Purpose: The aim of this study was to measure the peri-implant bone length surrounding implants that penetrate the sinus membrane at the posterior maxilla and to evaluate the survival rate of these implants. Methods: Treatment records and orthopantomographs of 39 patients were reviewed and analyzed. The patients had partial edentulism at the posterior maxilla and limited vertical bone height below the maxillary sinus. Implants were inserted into the posterior maxilla, penetrating the sinus membrane. Four months after implant insertion, provisional resin restorations were temporarily cemented to the abutments and used for one month. Then, a final impression was taken at the abutment level, and final cement-retained restorations were delivered with mutually protected occlusion. The complications from the implant surgery were examined, the number of failed implants was counted, and the survival rate was calculated. The periimplant bone lengths were measured using radiographs. The changes in initial and final peri-implant bone lengths were statistically analyzed. Results: Nasal bleeding occurred after implant surgery in three patients. No other complications were found. There were no failures of the investigated implants, resulting in a survival rate of 100%. Significantly more bone gain around the implants (estimated difference=-0.6 mm, P=0.025) occurred when the initial residual bone height was less than 5 mm compared to the >5 mm groups. No significant change in peri-implant bone length was detected when the initial residual bone height was 5 mm or larger. Conclusions: This study suggests that implants penetrating the sinus membrane at the posterior maxilla in patients with limited vertical bone height may be safe and functional.

• Restorative Dentistry and Endodontics
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• v.41 no.4
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• pp.278-282
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• 2016

Objectives: Glass ionomer cements (GICs), which are biocompatible and adhesive to the tooth surface, are widely used nowadays for tooth restoration. They inhibit the demineralization and promote the remineralization of the tooth structure adjacent to the restoration, as well as interfere with bacterial growth. Hence, the present study was conducted to assess and compare the antimicrobial activity of three commercially available GICs against two cariogenic bacteria. Materials and Methods: An agar plate diffusion test was used for evaluating the antimicrobial effect of three different GICs (Fuji IX, Ketac Molar, and d-tech) on Streptococcus mutans (S. mutans) and Lactobacillus acidophilus (L. acidophilus). Thirty plates were prepared and divided into two groups. The first group was inoculated with S. mutans, and the second group was inoculated with L. acidophilus. These plates were then incubated at $37^{\circ}C$ for 24 hours. Zones of bacterial growth inhibition that formed around each well were recorded in millimeters (mm). Results: The zones of inhibition for Fuji IX, Ketac Molar, and d-tech on S. mutans were found to be $10.84{\pm}0.22mm$, $10.23{\pm}0.15mm$, and $15.65{\pm}0.31mm$, respectively, whereas those for L. acidophilus were found to be $10.43{\pm}0.12mm$, $10.16{\pm}0.11mm$, and $15.57{\pm}0.13mm$, respectively. Conclusions: D-tech cement performed better in terms of the zone of bacterial inhibition against the two test bacteria, than the other two tested glass ionomers.