• The Journal of Advanced Prosthodontics
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• v.15 no.3
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• pp.114-125
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• 2023

PURPOSE. The aim of the study was to evaluate the optical properties of new generation (3Y-TZP) monolithic zirconia (MZ) with different abutment types and resin cement shades. MATERIALS AND METHODS. A1/LT MZ specimens were prepared (10 × 12 × 1 mm, N = 30) and divided into 3 groups according to cement shades as transparent (Tr), yellow (Y) and opaque (O). Abutment specimens were obtained from 4 different materials including zirconia (Group Z), hybrid (Group H), titanium (Group T) and anodized yellow titanium (Group AT). MZ and abutment specimens were then cemented. L^*, a^*, and b^* parameters were obtained from MZ, MZ + abutment, and MZ + abutment + cement. ∆E₀₀₁^* (between MZ and MZ + abutment), ∆E₀₀₂^* (between MZ and MZ + abutment + cement) and ∆E₀₀₃^* (between MZ + abutment and MZ + abutment + cement) values were calculated. Statistical analyses included 2-way ANOVA, Bonferroni, and Paired Sample t-Tests (P < .05). RESULTS. Abutment types and resin cements had significant effect on L^*, a^*, b^*, ∆E₀₀₁^*, ∆E₀₀₂^*, and ∆E₀₀₃^* values (P < .001). Without cementation, whereas zirconia abutment resulted in the least discoloration (∆E₀₀₁^* = 0.68), titanium abutment caused the most discoloration (∆E₀₀₁^* = 4.99). The least ∆E₀₀₂^* = 0.68 value was seen using zirconia abutment after cementation with yellow shaded cement. Opaque shaded cement caused the most color change (∆E₀₀₃^* = 5.24). Cement application increased the L^* values in all groups. CONCLUSION. The least color change with/without cement was observed in crown configurations created with zirconia abutments. Zirconia and hybrid abutments produced significantly lower ∆E₀₀₂^* and ∆E₀₀₃^* values in combination with yellow shaded cement. The usage of opaque shaded cement in titanium/anodized titanium groups may enable the clinically unacceptable ∆E₀₀^* value to reach the acceptable level.

• Journal of Korean society of Dental Hygiene
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• v.4 no.2
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• pp.277-291
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• 2004

The purpose of this study is to analyze the dental hygienists' overall performance in operative restoration and the clinical performance in operative restoration according to dental hygienists' career and to provide basic data for establishing the appropriate range of dental hygienists' work. Subjects of this study are 339 dental hygienists working at dental clinic and hospital nationwide, selected by their working place, career, type of clinic, and location of clinical institution. The distribution of people who responded to the survey shows that 81 belong to beginner level(less than 2 years since entering clinic), 115 intermediate level(2 to 3 years since entering clinic), 81 higher level(4 to 5 years since entering clinic) and 62 advanced level(more than 6 years since their entering clinic). In terms of the types of clinical institution, 178 belong to dental clinics and 161 belong to dental hospitals. The survey used in this study are focused on perception about clinical performance in operative dentistry and adequacy of the work. Operative dentistry consists of operative restoration and endodontic therapy. The operative restoration consists of 15 categories such as patient welcoming, examination and diagnosis, planning of treatment, anesthesia, control of moisture, cavity preparation, pulp protection, matrix band application, amalgam filling, resin filling, glass ionomer cement filling, abrasive strip removal, rubber dam removal, bite check and polishing, patient education, and arrangement. The reliability was Cronbach's Alpha .9453. SPSS 10.0 for Windows was used to analyze the responses. One way ANOVA was utilized to verify the differences in the dental hygienists' job performance in operative restoration and their job performance according to career. When significant difference was found. Duncan multi comparison post hoc was done. To sum up the results of this study, patient welcoming look the first place in the operative restoration. It was followed by patient education, examination and diagnosis, introducing treatment plan, resin filling, glass ionomer cement filling, amalgam filling, bite check and polishing, anesthesia, pulp protection, control of moisture, abrasive strip removal, cavity preparation, matrix band application, rubber dam removal, and anesthesia. In terms of the clinical performance by career, there were significant differences in 19 activities such as medical eraluation, oral examination, patient charting, intra oral readio graphs, firm developing fixing mounting, curing light gun, education of attention content after operation. Based on the results of this study, the specific range of operative restoration for dental hygienists should be focused on providing basic data for dentists' diagnosis, alleviation of fear and aching accompanied by injection and anesthesia, data providing for dentists' decision of anesthesia degree, and maximization of control of moisture.

• Restorative Dentistry and Endodontics
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• v.16 no.2
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• pp.189-196
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• 1991

The purpose of this study was to observe the inital acidity of zinc phosphate cements(Confit and Super Cem), poly carboxylate cement(Unident and Poly F), zinc oxide engenol cement(Stailine Super EBA) and g1ass ionomer cement(Fuji ionomer) Each cement was manuplated in accordance with each manufacturer's direction. All cements were mixed at the room temperature of $23^{\circ}{\pm}$, $5^{\circ}C$, and the electrode of pH meter(Ionanalyzer) was inserted in the mixed cement, and the acidity of cement were measured for 20 minutes from begining of cement mixing at $23^{\circ}C$ and $37^{\circ}C$ Results were as follows 1. The acidity of all cements ranges from pH 3, 5 to 4, 5 at 2 minutes after the start of mixing 2. The value of pH at $23^{\circ}C$ was higher than the value of pH at $37^{\circ}C$ in all cements. 3. As the time elapsed, the pH in all cements rose. The 20 minutes after the start of mixing the range of acidity was from pH 5 to pH 6 except Poly F. 4. In polycarboxylate cement, the different value of acidity at $23^{\circ}C$ and $37^{\circ}C$ was greatest. 5. The curve pattern of acidity in Unident was similar to that in Poly F cement The pH value of Unident was higher then that of Poly F, and value of pH in the curve pattern of acidity in Confit were similar to those in Super cement.

• Restorative Dentistry and Endodontics
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• v.39 no.2
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• pp.137-142
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• 2014

This article presents the successful surgical management of a failed mineral trioxide aggregate (MTA) orthograde obturation of a tooth with a history of impact trauma and perforated internal root resorption. A symptomatic maxillary lateral incisor with a history of perforation due to internal root resorption and nonsurgical repair using MTA was referred. Unintentional overfill of the defect with MTA had occurred 4 yr before the initial visit. The excess MTA had since disappeared, and a radiolucent lesion adjacent to the perforation site was evident radiographically. Surgical endodontic retreatment was performed using calcium enriched mixture (CEM) cement as a repair material. Histological examination of the lesion revealed granulation tissue with chronic inflammation, and small fragments of MTA encapsulated within fibroconnective tissue. At the one and two year follow up exams, all signs and symptoms of disease had resolved and the tooth was functional. Complete radiographic healing of the lesion was observed two years after the initial visit. This case report illustrates how the selection of an appropriate approach to treatment of a perforation can affect the long term prognosis of a tooth. In addition, extrusion of MTA into a periradicular lesion should be avoided.

• Journal of the Korean Ceramic Society
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• v.56 no.4
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• pp.403-411
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• 2019

In this work, the hydration process and cytotoxicity of lab-synthesized experimental Portland cements (EPCs) were investigated for dental applications. For this purpose, EPCs were prepared using laboratory-synthesized clinker constituents, tricalcium silicate (C₃S), dicalcium silicate (C₂S), and tricalcium aluminate (C₃A). C-A was prepared by the Pechini method, whereas C₃S and C₂S were synthesized by solid-state reactions. The phase compositions were characterized by X-ray diffraction (XRD) analysis, and the hydration process of the individual constituents and their combinations, with and without the addition of gypsum, was investigated by electrochemical impedance spectroscopy (EIS). Furthermore, four EPC compositions were prepared using the lab-synthesized C-A, C₃S, and C₂S, and their hydration processes were examined by EIS, and their cytotoxicity to HPC and HIPC cells were tested by performing an XTT assay. None of the EPCs exhibited any significant cytotoxicity for 7 days, and no significant difference was observed in the cell viabilities of ProRoot MTA and EPCs. The results indicated that all the EPCs are sufficiently biocompatible with human dental pulp cells and can be potential substitutes for commercial dental cements.

• Journal of dental hygiene science
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• v.22 no.4
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• pp.206-214
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• 2022

Background: This study analyzed the practice of dental medical dispute prevention rules of dental hygienists to present an improvement plan for improving perceived importance and practice and provide data for the development of effective medical dispute prevention programs. Methods: A self-administered questionnaire survey was conducted targeting dental hygienists who were providing assistance at dental hospitals and dental clinics in Seoul and Gyeonggi-do regions from March 22 to April 28, 2022. The questionnaire collected from 273 dental hygienists consisted of eight questions on general characteristics, 30 questions on medical dispute experience, and 14 questions on medical dispute prevention. Results: Complaints showed a high experience rate in 'Consultation & reservation', medical disputes in 'Patient handling (unkind) related', and 'Prosthesis installation and cement removal'. In both the importance and practice of medical dispute prevention rules, 'Preservation of medical records and other medical-related data' was high, and 'Management of patients on standby for a long time' was low in terms of practice. 'Lack of time' and 'Lack of manpower' were cited as reasons for not resolving dental treatment disputes. The importance of dental dispute prevention rules was found to be significant according to age and position, and it was also found to affect the level of practice. Conclusion: Seventy-six-point six percent of the respondents said that education on the prevention of medical disputes was necessary, although they lacked recognition of prevention rules compared to their perceptions and experiences. This study suggested specifying prevention rules in dental hygiene subjects and expanding education, improvement of dental treatment system, revise the law on the range of work to improve the recognition and practice of prevention rules.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.4819-4825
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• 2010

In all of dental ceramics, these materials contained the radio-isotopes with natural abundance ratio. After dental treatment, remained dental ceramics in the oral cavity is caused for human internal dose. In this study, the gross beta activity levels were measured in dental materials including 22 dental ceramics, 1 resin, and 2 cements for estimation of human internal dose. In dental ceramic samples, the obtained results showed that the gross beta activity level varied between 1.317 ~ 2.935 Bq/g and the gross beta activity level was 2.379 Bq/g. And the same level for dentine, opacious dentine, translucent and enamel were 2.479 Bq/g, 2.491 Bq/g, 2.470 Bq/g and 2.069 Bq/g, respectively. The gross beta activity level of temporary resin and cements were negligible, compare to the same level of dental ceramics. The high gross beta activity level observed in opacious dentine code OD-A4 is 2.935 Bq/g thus mainly ascribable to 40K. The reduction of the radiation level of natural radio-isotopes and the improvement of the dental ceramic materials should be required for internal dose reduction.

• Restorative Dentistry and Endodontics
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• v.39 no.2
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• pp.95-103
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• 2014

Objectives: This study evaluated the effect of three antioxidizing agents on pullout bond strengths of dentin treated with sodium hypochlorite. Materials and Methods: Root canals of 75 single-rooted human teeth were prepared. Fifteen teeth were irrigated with normal saline for a negative control group, and the remaining 60 teeth (groups 2 - 5) with 2.5% NaOCl. The teeth in group 2 served as a positive control. Prior to post cementation, the root canals in groups 3 - 5 were irrigated with three antioxidizing agents including 10% rosmarinic acid (RA, Baridge essence), 10% hesperidin (HPN, Sigma), and 10% sodium ascorbate hydrogel (SA, AppliChem). Seventy-five spreaders (#55, taper .02, Produits Dentaires S.A) were coated with silica and silanized with the Rocatec system and ceramic bond. All the prepared spreaders were cemented with a self-adhesive resin cement (Bifix SE, Voco Gmbh) in the prepared canals. After storage in distilled water (24 h/$37^{\circ}C$), the spreaders were pulled out in a universal testing machine at a crosshead speed of 1.0 mm/min. Pull-out strength values were analyzed by one-way ANOVA and Tukey's HSD test (${\alpha}$ = 0.05). Results: There were significant differences between study groups (p = 0.016). The highest pullout strength was related to the SA group. The lowest strength was obtained in the positive control group. Conclusions: Irrigation with NaOCl during canal preparation decreased bond strength of resin cement to root dentin. Amongst the antioxidants tested, SA had superior results in reversing the diminishing effect of NaOCl irrigation on the bond strength to root dentin.

• The Journal of Advanced Prosthodontics
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• v.5 no.2
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• pp.126-132
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• 2013

PURPOSE. Post surface conditioning is necessary to expose the glass fibers to enable bonding between fiber post and resin cement. The purpose of the present study was to evaluate the effect of different surface conditioning on tensile bond strength (TBS) of a glass fiber reinforced post to resin cement. MATERIALS AND METHODS. In this in vitro study, 40 extracted single canal central incisors were endodontically treated and post spaces were prepared. The teeth were divided into four groups according to the methods of post surface treatment (n=10): 1) Silanization after etching with 20% $H_2O_2$, 2) Silanization after airborne-particle abrasion, 3) Silanization, and 4) No conditioning (Control). Adhesive resin cement (Panavia F 2.0) was used for cementation of the fiber posts to the root canal dentin. Three slices of 3 mm thick were obtained from each root. A universal testing machine was used with a cross-head speed of 1 mm/minute for performing the push-out tests. Two-way ANOVA and Tukey post hoc tests were used for analyzing data (${\alpha}$=0.05). RESULTS. It is revealed that different surface treatments and root dentin regions had significant effects on TBS, but the interaction between surface treatments and root canal regions had no significant effect on TBS. There was significant difference among $H_2O_2$ + Silane Group and other three groups. CONCLUSION. There were significant differences among the mean TBS values of different surface treatments. Application of hydrogen peroxide before silanization increased the bond strength between resin cements and fiber posts. The mean TBS mean values was significantly greater in the coronal region of root canal than the middle and apical thirds.

• Restorative Dentistry and Endodontics
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• v.47 no.3
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• pp.31.1-31.9
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• 2022

Objectives: This study aimed to evaluate in vitro the effects of the self-adhesive resin cements RelyX U200 (3M ESPE) and seT PP (SDI Limited) on murine macrophages and the interference of the photoactivation. Materials and Methods: Cell viability assays, cell adherence, yeast phagocytosis of Saccharomyces boulardii and production of reactive oxygen species (ROS) were performed in the presence of capillaries containing the respective self-adhesive cement when photoactivated or not. Results: After long periods of contact, both types of cements, when not photoactivated, are more cytotoxic for macrophages. The seT PP cement when only chemically activated seems to interfere more negatively in the process of phagocytosis of yeasts S. boulardii. Both types of cements interfere in the cell adhesion process, independent of photoactivation. None of the types of cements tested was able to induce the production of ROS. Conclusions: Our results highlight the great importance of the photoactivation of self-adhesive resin cements in the dental clinic, since RelyX U200, when photoactivated, presented the best results within the evaluated parameters.