Temp Bond NE Research Articles

Effect of crown seating methods on the remnant cement in the subgingival region of a cement-retained implant crown

This study aimed to investigate the effects of crown seating speed, crown seating force, quantity of cement used, and type of implant cement on the amount of remnant cement in the subgingival region (RCS) after cementation. Cement-retained implant crowns were cemented to titanium abutments using the following methods: four types of implant cement (TBN: TEMP BOND NE, NR: NEXUS RMGI, ME: MAXCEM ELITE, and U200: RELYX U200), three quantities of cement (0.02 ml, 0.04 ml, and 0.06 ml), three crown seating speeds (5 mm/s, 10 mm/s, and 15 mm/s), and two crown seating forces (25 N, 50 N). The surface area and length of the RCS were measured using a 3D intraoral scanner. The total RCS weight was measured using an analytical balance. The RCS increased significantly as the seating speed increased, the seating force increased, and the quantity of cement increased (p < 0.05). The RCS values were the highest for TBN, followed by U200, NR, and ME (p < 0.05). The lower seating speed, smaller quantity of cement used, and smaller seating force applied in cement-retained implant restorations minimized the RCS in cement-retained prostheses. The type of cement is a factor that determines the aspects of the RCS.

Тимчасові незнімні ортопедичні конструкції виготовлені із використанням CAD/CAM системи методом фрезерування, як альтернатива постійним на тривалий термін

Relevance. Prevalence of partial loss of teeth in the population of Ukraine is from 62.3% to 84.5%. The war in Ukraine significantly affected the provision of timely and high-quality dental care. However, the restoration of the destroyed crown part of the tooth and the integrity of the tooth rows must take place in a timely manner, as it leads to the development of secondary deformations of the dental and jaw system. One of the options for solving the problem of timely orthopedic treatment, in these conditions, can be the use of temporary fixed orthopedic structures made using the CAD/CAM system by the milling method. The aim is to investigate the possibility of using non-removable temporary orthopedic structures made using the CAD/ CAM system by the milling method and cements for their temporary fixation for a period exceeding that established by the general protocols of orthopedic treatment and declared by the manufacturer. Materials and methods. The study was conducted in the period from September 2022 to April 2024 at the Department of Orthopedic Stomatology of the National Medical University named after O.O. Bogomolets For the study, 60 patients aged 25-59 years were selected, with the destruction of the crown part of the tooth, which required replacement with a fixed orthopedic structure and included dentition defects of various lengths. All supporting elements were divided into groups, depending on the cement used for fixation: Group I – Freegenol (GC, Japan), Group II – Provicol (Voco, Germany), Group III – RelyX Temp NE (3M ESPE, Germany), IV group – Temp-Bond NE (KERR, USA). Re-examinations of patients were carried out in periods from two weeks to six months. Results. Depending on the selected cement for temporary fixation of a non-removable orthopedic structure, the percentage of decementing of temporary single crowns, in terms of two weeks to six months, was from 2.22% to 32.65%, structures with support on two elements from 5.55% to 52.94% and based on three elements from 7.14% to 77.78%. A direct relationship was established between the appearance of mobility of the temporary fixed orthopedic structure, the sensitivity of the vital tooth and bleeding gums in all groups of subjects. Conclusions. Temporary non-removable orthopedic structures made using the CAD/CAM system by the milling method, depending on the selected cement for temporary fixation, can be used to restore the crown part of the tooth and included defects of the dentition for a period that exceeds that established by the general protocols of orthopedic treatment and declared by the manufacturer. Key words: temporary non-removable orthopedic structures, CAD/CAM systems, milling, cements for temporary fixation.

Evaluation of the effect of surface roughness and modification of implant abutment axial wall on the retention of zirconium oxide copings before and after thermocycling.

The purpose of this study was to determine the effect of one-wall elimination of the abutment and also the surface treatment of the abutment on the retention of cement-retained, implant-supported zirconium oxide copings. In this experimental study, four straight abutments were connected to four implant analogs (DIO, UF, Busan, Korea) with 35 Ncm torque. They are mounted vertically in resin blocks. Abutments were prepared as following groups: A) abutment was used in its intact standard form as a control group. B) 4 mm of the flat wall was removed to produce an abutment with 3 walls. C) The abutment surface was abraded with 50 µm AL2O3 powder. D) 4 mm of a flat wall of the abutment was removed, then the abutment surface was abraded with 50 µm AL2O3 airborne particle.10 zirconium oxide copings were made. Samples were cemented with temp bond NE to abutments. The retention of copings was measured before and after incubation using the universal testing machine. T-test, one-way ANOVA, and Post Hoc Tukey Test were used for statistical analysis of data. In all groups, retention was decreased after thermocycling (P ≤0.001). 3 wall abutments had less retention than the control group before thermocycling. A significant difference was detected between 3 wall abutments and 4 walls of sandblasted abutments before thermocycling. After thermocycling, no difference in retention was seen between groups. Thermocycling significantly reduces the retention of implant-supported ceramic copings. Sandblasting abutments with 50 µm AL2O3 air-borne particles did not increase the retention of ziconium oxide copings which were cemented with temp bond NE. One wall elimination of abutment decreased the retention of zirconia copings. Key words:Retention, crown, abutment, zirconia coping, sandblasting.

The effect of three dental cement types on the corrosion of dental implant surfaces

Statement of problemOne of the main challenges facing dental implant success is peri-implantitis. Recent evidence indicates that titanium (Ti) corrosion products and undetected-residual cement are potential risk factors for peri-implantitis. The literature on the impact of various types of dental cement on Ti corrosion is very limited. PurposeThis study aimed to determine the influence of dental cement on Ti corrosion as a function of cement amount and type. Materials and methodsThirty commercially pure Ti grade 4 discs (19 × 7mm) were polished to mirror-shine (Ra ≈ 40 nm). Samples were divided into 10 groups (n = 3) as a cement type and amount function. The groups were no-cement as control, TempBond NE (TB3mm, TB5mm, and TB8mm), FujiCEM-II (FC3mm, FC5mm, and FC8mm), and Panavia-F-2.0 (PC3mm, PC5mm, and PC8mm). Tafel’s method estimated corrosion rate (icorr) and corresponding potential (Ecorr) from potentiodynamic curves. Electrochemical Impedance Spectroscopy (EIS) data was utilized to obtain Nyquist and Bode plots. An equivalent electrical circuit estimated polarization resistance (Rp) and double-layer capacitance (Cdl). Inductively coupled plasma mass spectrometry (ICP-MS) analysis was conducted to analyze the electrolyte solution after corrosion. pH measurements of the electrolyte were recorded before and after corrosion tests. Finally, the corroded surface was characterized by a 3D white-light microscope and scanning electron microscope. Statistical analysis was conducted using either one-way ANOVA followed by Tukey’s Post Hoc test or Kruskal-Wallis followed by Dunn’s test based on data distribution. ResultsBased on cement amount, FC and PC significantly increased icorr in higher amounts (FC8mm-icorr = 8.22 × 10−8A/cm2, PC8mm-icorr = 5.61 × 10−8A/cm2) compared to control (3.35 × 10−8A/cm2). In contrast, TB3mm decreased icorr significantly compared to the control. As a function of cement type, FC increased icorr the most. EIS data agrees with these observations. Finally, corroded surfaces had higher surface roughness (Ra) compared to non-corroded surfaces. ConclusionThe study indicated that cement types FC and PC led to increased Ti-corrosion as a function of a higher amount. Hence, the implant stability could be impacted by the selection, excessive cement, and a potentially increased risk of peri-implantitis.

Optical properties of esthetic temporary cements and final restoration color

BackgroundOpaque cements can be esthetically unfavorable and alternative translucent materials have been developed. The aim of this study was to evaluate the color interference of a new translucent cement compared with conventional materials, in association with interim restoration with different thickness and shades. MethodsBis-acryl composite disks were prepared in 2 thicknesses (1.2 mm, 0.6 mm) and 3 shades (A3.5, A2, bleached) to simulate the restorations. Cementation over dentin disks was performed with 1 translucent cement (Provicol QM Aesthetic; VOCO), 2 conventional cements (Provicol; VOCO, Temp-Bond NE; Kerr Dental), and 1 transparent liquid (polyethylene glycol 400). The difference between the color of the specimens cemented with the transparent liquid and that of the specimens cemented with each cement was calculated (ΔEab). The data were analyzed using 3-way analysis of variance and Tukey tests (5%). ResultsSignificant differences were observed for all factors and some interactions (P < .05). For Provicol QM Aesthetic, the shade and thickness did not influence the ΔEab. For Provicol and Temp-Bond NE, the lighter and thinner the specimen, the higher the ΔEab. Only Provicol QM Aesthetic had smaller means than the perceptibility threshold. Temp-Bond NE and Provicol had higher values than the acceptability threshold for some combinations. ConclusionsThe highly translucent cement had less color interference than the conventional materials. The thickness and resin shade only affected the results for the opaque cements. The thinner specimens and the lighter shades had higher color interference. Practical ImplicationsThe use of a more translucent cement can produce a smaller color interference on the esthetic outcome of interim restorations.

The Effect of the Digital Manufacturing Technique, Preparation Taper, and Cement Type on the Retention of Aged Anterior Provisional Crowns: An In Vitro Study

A well-made provisional fixed prosthesis must present as a preview of the future prosthesis and may also augment the health of the abutments and periodontium. Provisional restorations have been prepared chairside with polymethyl methacrylate (PMMA) since time immemorial. CAD/CAM additive and subtractive technologies have revolutionized the fabrication of interim restorations in dental clinics. The current literature lacks substantial data about retention of provisional crowns manufactured using Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) additive and subtractive techniques with various temporary cements. This in vitro study aims to assess and compare the retention of temporary/provisional anterior crowns based on the combined effect of different digital manufacturing techniques, preparation tapers, and the temporary cements used for cementation. Two maxillary right central incisor typodont teeth were prepared to receive all-ceramic crowns, one with a 10-degree taper and the other with a 20-degree taper. Forty 3D-printed working models with the 10° taper and forty working models with the 20° taper were prepared to receive the temporary crowns. Forty temporary crowns were 3D-printed and forty crowns were milled (20 from each taper group). Kerr Temp-Bond NE conventional cement and Kerr Temp-Bond clear cement were used for cementation in the two groups. The number of samples per test group was 10. All samples were thermocycled and subjected to a universal testing machine to measure the pull-off force until retention loss (N) under tension with a crosshead speed of 5 mm/min. The pull-off force was highest for group 8, i.e., 3D-printed crowns with a 20° taper and cemented with Kerr Temp-Bond clear cement, followed by groups 6, 7, 4, 5, 3, and 2. Group 1, i.e., milled crowns with 10° taper cemented with Kerr Temp-Bond NE conventional cement, exhibited the lowest pull-off retentive force. The clinical selection of long-term provisional crowns fabricated using 3D-printing technology, prepared with 10° or 20° tapers, and cemented with clear cement, is the most favorable in terms of the retention of provisional crowns. 3D-printed provisional crowns can be used as an alternative to conventional and CAD/CAM-milled crowns for long-term provisionalization.

Retention of different temporary cements tested on zirconia crowns and titanium abutments in vitro

PurposeThe aim of the present study was to examine the retention force of monolithic zirconia copings cemented with various temporary cements on implant abutments in vitro.MethodsSixty exercise implants with pre-screwed implant abutments were embedded in resin. Subsequently, 60 CAD/CAM manufactured zirconia copings were divided into three main groups [Harvard Implant Semi-permanent (HAV), implantlink semi Forte (IMP), Temp Bond NE (TBNE)]. The zirconia copings were cemented on the implant abutments and loaded with 35 N. Specimens were stored in distilled water (37 °C) for 24 h. Half of the test specimens of each group were subjected to a thermocycling (TC) process. Retention force was measured in a universal testing machine. Using magnifying glasses, the fracture mode was determined. Statistical analysis was performed applying the Kruskal-Wallis test, the post hoc test according to Dunn-Bonferroni and a chi-square test of independence.ResultsWithout TC, IMP showed the highest retention of the three temporary luting agents (100.5 ± 39.14 N). The measured retention forces of IMP were higher than those of HAV (45.78 ± 15.66 N) and TBNE (61.16 ± 20.19 N). After TC, retention was reduced. IMP showed the greatest retentive strength (21.69 ± 13.61 N, three fail outs). HAV and TBNE showed pull-off forces of similar magnitude (17.38 ± 12.77 N and 16.97 ± 12.36 N, two fail outs). The fracture mode analysis showed different results regarding the tested cements before and after TC (facture type before/after TC): IMP (III+II/III), HAV (I/II) and TBNE (III/III). There were clear differences of the fracture modes regarding the examination before and after TC.ConclusionsWithin the limits of this study, IMP showed the highest pull-off forces under the chosen test conditions. All three temporary luting agents showed lower retention forces after TC. Retention values in the individual cement classes were very heterogeneous. Easy cement removal in the crown lumen favours the dominance of adhesive cement fractures on the abutment and adhesive/cohesive cement fractures on the abutment with HAV appears advantageous in case of recementation of the superstructure.

Microleakage of different temporary luting agents used for cementing provisional restorations on custom cast posts and cores

This study aimed to compare the effect of four temporary luting agents on preventing the coronal microleakage of teeth restored with custom cast post and core. In this in vitro original study, after removing 9 mm of gutta percha from root canals of 32 single-canaled premolars, the acrylic resin patterns of the post and core were fabricated. Patterns were cast with Ni-Cr metal alloy and then cemented with glass ionomer. Using self-curing acrylic resin, provisional restorations were made. Then, teeth were randomly allocated to four groups for each temporary cement including zinc oxide eugenol (Temp Bond), zinc oxide noneugenol (Temp Bond NE), noneugenol resin-based temporary luting agent (Temp Bond Clear), and noneugenol urethane methacrylate polymer-based temporary luting agent (Dento temp). Teeth were subjected to thermocycling, immersed in silver nitrate for 6 h and then sectioned. The amount of dye penetration in the margin of provisional crown and into the coronal part of the root canals was measured using a stereomicroscope. Data were analyzed using the Kruskal-Wallis and Dunn tests with significance level of 0.05. All the luting agents showed some degree of microleakage (Group 1 showed the most microleakage). According to the pair comparison between the groups, Group 1 revealed a significant difference with others (P < 0.05). Furthermore, Group 2 showed more microleakage as compared to Group 4 (P = 0.037). Temp Bond showed the highest microleakage as compared to other luting agents. Furthermore, Temp Bond NE revealed a weaker sealability as compared to Dento temp.

Determination of biofilm forming activity of microorganisms on synthetic polymeric materials.

Microorganisms are able to form biofilms on surfaces of biotic and abiotic nature. In turn, in human biotopes there are optimal conditions for the implementation of biofilm-forming activity. Moreover, in medical practice, polymeric materials are often used for drainage or prosthetics, which can also be successfully colonized by bacteria. However, in laboratory practice, the formation of biofilms is usually evaluated on glass or polystyrene. The purpose of the study is to evaluate the methodological features of studying the biofilm-forming activity of microorganisms on the surface of synthetic polymeric materials. We used strains of Staphylococcus aureus ATCC 25923, Escherichia coli K-12, Candida albicans ATCC 10231, as well as synthetic polymeric materials - DentLight Flow light-curing composite material (nano-hybrid fluid composite; Russia), glass ionomer chemical curing Fuji 1 (Japan), cement for temporary fixation of orthopedic constructions TempBond NE (USA), acrylic, polyurethane and polyvinyl chloride. The formation of biofilms in flat-bottomed ELISA plates in this study was considered as a control group. If the polymer belonged to cold curing materials, sterile flat-bottomed tablets were used, the bottom of which was filled with a thin layer of plastic. After hardening of the plastic, biofilms were formed in the tablets. In the second series of experiments, hot cured materials cut into equal parts 5×5×1 mm in size were placed in the wells of a plate and again used to determine biofilm formation with subsequent coloring. To extract the dye, the pieces were transferred to a new plate to exclude the amount of film biomass formed on the walls of the plate wells. In both cases, cultivation was carried out at 37° C for 24-48 hours. The biomass of the film was stained with fuchsin. Statistical data processing was performed using t-Student criterion. For the threshold level of significance, the value p <0.05 was taken. It is established that the proposed options for determining biofilm forming ability are available and indicative. It was revealed that the same microorganisms have individual biofilm formation indicators for each polymer material. The light curing dental composite and polyvinyl chloride exhibit the more pronounced antiadhesive properties than cements and polyurethane. Up to date, most of the studies of biofilm formation have been carried out using glass or polystyrene, which, as a rule, are not used for the manufacture of prostheses, catheters, drains, etc., which makes it difficult to assess the true film-forming activity of microorganisms. The proposed methodological approaches, especially the second option for preparing testing samples, solve this problem. In general, the proposed approaches to testing biofilm-forming activity on polymers are very simple to implement and generally available. For an adequate study of the biofilms formation, it will be advisable to use polymer materials, directly used in medicine, rather than polystyrene tablets, the material of which is found exclusively in laboratory practice.

Assessment of the internal fit and marginal integrity of interim crowns made by different manufacturing methods

Statement of problemThe adaptation of interim crowns made by subtractive and additive manufacturing has not been well investigated. PurposeThe purpose of this in vitro study was to evaluate the internal fit and marginal discrepancy of interim crowns made by different manufacturing methods. Material and methodsA dentoform mandibular left first molar was prepared for a ceramic crown and scanned for the fabrication of 48 stereolithical resin dies and interim crowns. Group CAM included 16 ZCAD interim crowns made by computer-aided design and computer-aided manufacturing (CAD-CAM) technology; group 3DP, 16 NextDent MFH interim crowns made by digital light processing technology; and group APP, 16 Jet interim crowns manually made by using autopolymerizing acrylic resin and used as controls. The silicone replica technique was used to determine the internal discrepancy volume before definitive cementation. All crowns were cemented with Temp-Bond NE under a 50-N load and bench set for 10 minutes before microcomputed tomographic (μCT) scan assessment. The volume of cement space was measured by using the μCT scan 3-dimensional (3D) images, and gap distance at assigned locations was recorded by using the μCT scan 2-dimensional (2D) images. The marginal discrepancy was measured by the polyvinyl siloxane (PVS) impression technique and using a stereomicroscope. Data were analyzed by ANOVA and the Tukey honestly significant difference tests (α=.05). The association between different measuring techniques was analyzed by the Pearson correlation test. ResultsThe gap distance between interim crowns and dies from all 3 groups measured by using the μCT scan 2D images ranged from 0.13 mm to 0.55 mm, with the highest value found at the central occlusal location in group APP. The total average gap distance values recorded for group APP were significantly higher than those for group CAM and group 3DP (P<.05). No significant differences were found in internal discrepancy and cement space volume between group CAM and group 3DP (P>.05). The Pearson correlation test showed a moderate correlation (r=0.69) between the silicone replica technique and the μCT scan technique in determining cement space volume. When the PVS impression technique was used to measure the marginal discrepancy, the mean values obtained from group APP were statistically significantly higher than those from group CAM and group 3DP (P<.05). No statistically significant difference in marginal discrepancy was found between group CAM and group 3DP (P=.70). ConclusionsDigitally fabricated interim crowns had better internal fit and smaller marginal discrepancy than manually constructed interim crowns. The silicone replica technique and μCT scan technique measurements had a moderate correlation in assessing the adaptation of cemented interim crowns.

Influence of margin location and luting material on the amount of undetected cement excess on CAD/CAM implant abutments and cement-retained zirconia crowns: an in-vitro study

BackgroundThe flexibility in designing the submucosal part of CAD/CAM customized implant abutments and the individual positioning of its shoulder line has been suggested to reduce the risk of leaving undetected cement residues, thus preventing adverse effects on peri-implant tissues. A high correlation between excess cement left in the soft tissues and the occurrence of increased biofilm accumulation with sulcular bleeding and/ or suppuration has been reported. This in turn may cause peri-implant inflammation and peri-implant marginal bone loss. The aim of this study was to assess the frequency of cement remnants after the luting of zirconia crowns on CAD/CAM custom molar abutments with different margin levels and to evaluate the impact of the luting material.Material and methodsA total of 20 titanium molar CAD/CAM implant abutments (BEGO Medical GmbH) with internal taper connection/ internal hex anti-rotation protection, and a convex emergence profile with different margin positions (0, 1, 2 and 3 mm below the mucosa), were virtually designed (Implant Studio, 3Shape) and manufactured. A master cast was scanned, duplicated by a 3D printer and individual gingival masks were produced to simulate peri-implant soft tissues. 20 corresponding zirconia crowns were designed (Cerec 3D, Dentsply Sirona), produced and cemented to the abutments with two different luting materials; a zinc oxide non-eugenol cement (Temp Bond NE) or a methacrylate cement (Panavia V5). To ensure retrievability of the crown/abutment connection, occlusal openings providing access to the abutment screws were designed. Excess cement was thoroughly removed and the crown/abutment units were unscrewed to evaluate the occurrence of cement residues. All the quadrants of each specimen were evaluated for calculation of the ratio between the cement remnant area and the total specimen area using Adobe Photoshop. Spearman analysis was performed to detect correlations between different variables. A two-sided t-test, ANOVA, Mann–Whitney, and Kruskal–Wallis tests were applied to detect differences between the groups.ResultsCement remnants were found in every depth of the crown abutment complex and in almost every area investigated. The amount of cement residues increased as the crown-abutment margin was located more submucosally. Lingual areas were more prone to cement remnants than other surface areas (p = 0.0291). Excess cement was not only found at the margins of the crown-abutment complex, but also underneath (basal) the abutment itself, where cleaning was impossible. No statistical difference in the effect of zinc oxide non-eugenol- and methacrylate cement on the frequency of excess material at the lateral abutment surfaces could be demonstrated in vitro. The proportion of basal abutment aspects covered with cement residues was, however, significantly smaller in Panavia V5 samples with an average of 4.9 ± 3.7% compared to Temp Bond samples with an average of 8.6 ± 5.5%.ConclusionsGiven the results obtained in the present investigation the margin of CAD/CAM molar abutments should be located as coronally as possible to minimize the amount of cement remnants. If an epigingival or supragingival margin location is not feasible due to esthetic concerns, it cannot be recommended to place the margin of molar CAD/CAM abutments deeper than 1.5 mm in the proximal and oral regions.

On the understanding of zinc-oxide eugenol cement use prior to etch-rinse bonding strategies.

Zinc-oxide eugenol (ZOE) is frequently used due to its satisfactory biological response, sedative effect on the pulp, and easy removal. However, literature is very controversial about the influence of the temporary cement-containing eugenol on the bond strength properties. This study aims to clarify the literature controversy by evaluating the bond strength of ZOE or ZOE-free applied before bonding procedures and the 7-day resting period after the first session. Twelve recently extracted third molars were randomly divided into three groups: Group 1: Control (without treatment), Group 2: Temp-Bond NE; Group 3: Temp-Bond. After temporary restorations, the teeth were immersed in distilled water and stored for 7 days at 37°C. The temporary cement was mechanically removed, and prophylaxis was performed. The adhesive procedures were performed, and a 6-mm-high composite resin block was built. The teeth were immediately stored at 100% relative humidity at 37°C for 24 hours. Specimens with 0.7 (±0.2) mm2 of cross-sectional area were obtained and subjected to a microtensile bond strength (μTBS) test at 1 mm/min until failure. Analysis of variance (ANOVA) and Tukey's post hoc test were used for statistical analysis. ZOE or ZOE-free cement did not interfere in the μTBS between resin composite and dentine when used with a two-step-etch-rinse adhesive material, considering 7 days of resting period after the first session, by the ANOVA and Tukey's post hoc test (P < 0.05). The authors recommend the removal of the temporary cementation at least seven days after the first session and suggest that the clinicians follow-up further studies to use the cement in case its removal is recommended within a longer period.

Effect of cement application techniques on the adaptation and retention of provisional crowns.

A well-made and properly cemented provisional restoration is essential for the health of abutment teeth and periodontium. Few focused studies are available on the effect of cementation techniques on the fit as well as on the retention of the provisional crowns. To investigate the effect of six cement application techniques on the adaptation and retention of provisional crowns. Seventy-two provisional crowns (Bisacryl resin) were fabricated over identical self-cured resin dies and were divided into six groups (N= 72; 6 ×n= 12) of cement application techniques (Temp Bond NE, Kerr Corporation). Group-A (Bulk Fill); Group-B (Cement on inner walls); Group-C (Cement on axial walls); Group-D (Cement on crown margin); Group-E (Cement on tooth margin); Group-F (Cement with vent-holes). Adaptation was assessed before and after cementation with digital caliper (0.001mm). Universal testing machine was used for retention measurement in Mega Pascal's (MPa). Data was analyzed by SPSS using Paired T-Test and Tukey's test (p< 0.05). The highest and lowest difference between the two measurements was observed for the Group A (0.095mm) and Group C (0.030mm) respectively. Paired T-Test revealed significance (p< 0.05) between before and after cementation. Group-F (0.6094MPa) and Group-E (0.1858MPa) showed the highest and lowest retention respectively. Group-E (Cement on tooth margin) with lowest retention significantly differed (Tukey's Test; p< 0.05) from other groups. Bulk filling of the provisional crown with luting cement significantly increases the adaptation discrepancies. Discrepancies are more when luting cement is applied on the occlusal surface of the crowns. However, it didn't influence the retention of the crowns. Cement application on axial walls and cervical third of intaglio surface of crowns was the method of choice with regards to adaptation and retention combined. Addition of vent-holes improved the adaptation with best possible retention.

Influence of margin location and luting material on the amount of undetected cement excess on CAD CAM implant abutments and cement‐retained zirconia crowns

Background As cement remnants of fixed implant-supported restorations have been associated with clinical and radiographic signs of peri-implantitis, there is a need for reducing the probability of leaving subgingival cement excess. High flexibility in designing the subgingival part of CAD CAM abutments and the individual positioning of the shoulder finish line may eliminate the problem of undetected cement residues. However, so far there is only little data available to support this hypothesis. Aim/Hypothesis To test whether or not an epimucosal position of an abutment margin with temporary zinc oxide non-eugenol cement or methacrylate cement is superior to a submucosal margin position in terms of remaining cement following cementation of reconstructions on customized CAD CAM molar abutments. Material and Methods A total of 20 titanium CAD CAM abutments (Semados, BEGO, Bremen, Germany) with a convex emergence profile and different margin positions (from 0 to 1, 2, and 3 mm below the mucosa) were virtually designed and centrally manufactured. The master cast was scanned, duplicated by a 3D printer, and individual gingival masks were produced to simulate peri-implant soft tissues. 20 zirconia crowns (Zirlux, Henry Schein, Germany) were produced and cemented to the abutments with two different luting materials (Temp Bond NE, Kerr Dental, Germany, Panavia V5, Kuraray, Japan). To ensure retrievability of the crown abutment connection, occlusal openings providing access to the abutment screws were designed. Cement excess was thoroughly removed and the crown abutment units were unscrewed to evaluate the occurrence of cement residues. All quadrants of each specimen were evaluated for calculation of the ratio between the cement remnant area and the total specimen area using Adobe Photoshop (p 0.05). Results Cement remnants were found in every depth of the crown abutment complex and in almost every area investigated. The amount of cement residues was influenced by the location of the crown-abutment margin. A significant increase in remnants was detected when the crown-abutment margin was located more submucosally. Deep crown–abutment margin positions (deeper than 1 mm below mucosa) increased the risk of cement excess. Oral and interdental areas are more prone to cement remnants than other surface areas. The investigation showed, that cement remnants were not only found at the margins of the crown-abutment complex, but also underneath (basal) of the abutment itself, where literally no cleaning was possible at all. No statistical difference in the effect of a temporary zinc oxide non-eugenol cement (Temp Bond NE, Kerr Dental) and a methacrylate cement (Panavia V5, Kuraray, Japan) on the frequency of excess cement could be demonstrated. Conclusions and Clinical Implications Given the results obtained in the present investigation the margin of CAD CAM molar abutments should be located as coronally as possible to minimize the amount of cement remnants. Due to esthetic reasons this ideal margin location is frequently not feasible. However, it cannot be recommended to place the margin of molar abutments deeper than 1.5 mm in the interdental and oral regions. There was no evidence that the type of cement had an influence on the amount of remnants after cleaning.

Influence of Luting Materials on the Retention of Cemented Implant-Supported Crowns: An In Vitro Study.

The retention force of cemented crowns on implant abutments with various luting materials was evaluated. Cobalt–chromium crowns were cemented onto tapered titanium abutments (Camlog) with eugenol-free temporary cement (RelyX TempBond NE), composite-based temporary cement (Bifix Temp), zinc phosphate cement (Harvard Cement), glass-ionomer cements (Meron, Fuji I), and resin-modified glass-ionomer cements (Fuji II, Fuji Plus, Ketac Cem Plus). Specimen aging via hydrostress was performed in artificial saliva at 37 °C for 14 days (S1), followed by hydrothermal stress with thermocycling (S2). The crowns were removed, and the force was recorded (T1). Subsequently, the crowns were recemented, aged, and removed, and the force was recorded (T2, T3). The retention forces differences were statistically significant according to the storage conditions at T1 (p = 0.002) and T3 (p = 0.0002). After aging (S1), Ketac Cem Plus had the highest retention force median value difference (T3 versus T1) (−773 N), whereas RelyX TempBond NE had the lowest (−146 N). After aging (S2), Meron had the highest retention force median value difference (−783 N), whereas RelyX TempBond NE had the lowest (−168 N). Recementation decreased the retention force of the implant-supported cobalt–chromium crowns cemented and recemented with the same luting materials. Luting materials (at T1) and aging conditions significantly impacted the retention force.

Antibacterial Effect of a Temporary Cement-Dissolving Liquid.

Methods for removing temporary cement with an antibacterial effect might improve prosthetic treatment prognosis. Three removal methods were assessed: (1) immersion of an acrylic provisional restoration in a temporary cement dissolver (Temp-off); (2) mechanical removal with a dental explorer; and (3) sandblasting. Two temporary cements, one with eugenol (Temp-Bond) and one without eugenol (Temp-Bond NE) and of two thicknesses (100 μm and 250 μm), were examined. Immersion in Temp-off produced the most effective bacterial count decrease compared to the other methods (P < .05). No significant difference was found between the two cement types, although the decrease in count was more evident in the thicker (250 μm) cement layer. Temp-off dissolving liquid used for removal of temporary cement exhibited an antibacterial effect and nonmechanical cleaning ability.

Influence of additional reinforcement of fixed long-term temporary restorations on fracture load

PurposeIn implant dentistry, temporary restorations (TR) might often be required for up to one year. The aim of this in vitro study was to evaluate the long-time performance of four-unit TRs in the posterior region based on different materials and reinforcement methods. MethodsOne hundred and forty four TRs were manufactured on 16 models simulating an oral situation of two missing posterior teeth. With a computer-aided-design/computer-aided-manufacturing (CAD/CAM) workflow, a TR was fabricated (CAD; Telio CAD), which served as a template for other subgroups. With a vacuum-formed template, unreinforced and reinforced TRs [glass fibres (g; EverStick); polyethylenefibres (p; Ribbond original) and TRs with increased connector area (c; 27.5–35mm2)] were manufactured. Two different composite materials were used (C1: Luxatemp, C2: Protemp). Altogether, 16 subgroups with 8 specimens each were tested. After temporary luting (Temp Bond NE) and artificial-aging [1600 thermo-cycles (5–55°C), 240,000 chewing-cycles (50N)], all specimens were tested until fracture in a universal testing machine. ResultsAfter artificial aging, mean fracture loads (N) were: (C1)201.2±109.7, (C1c)1033.0±173.1, (C1p)90.0±40.0, (C1g)75.9±25.9, (C2)108.6±58.6, (C2c)1363.3±148.6, (C2p)104.7±54.7, (C2g)50.0±0.0 and (CAD)232.5±19.1. The one-factor ANOVA analysis showed significant differences for the factors temporary material (p<0.047), reinforcement (p<0.0001) and artificial-aging (p<0.0001). ConclusionsThe study indicated that both CAD/CAM TRs and TRs with increased connector areas are suitable for long-term use of one year. No enhancement of fracture load was observed for fibre-reinforced TRs except for the fact that fractured TRs were not totally separated.

Antibacterial activity against Streptococcus mutans and diametrical tensile strength of an interim cement modified with zinc oxide nanoparticles and terpenes: An in vitro study

Statement of problemInterim restorations are occasionally left in the mouth for extended periods and are susceptible to bacterial infiltration. Thus, dental interim cements with antibacterial properties are required. PurposeThe purpose of this in vitro study was to determine in vitro antibacterial activity against Streptococcus mutans and to compare the diametrical tensile strength (DTSs) of dental interim cement modified with zinc oxide nanoparticles (ZnO-NPs) with that of cement modified with terpenes. Material and methodsAntibacterial properties of ZnO-NPs, terpenes, and dental interim cement modified with ZnO-NPs and cement modified with terpenes against S mutans were tested according to minimum inhibitory concentration (MIC) and direct contact inhibition (DCI). Tensile strength levels were evaluated using DTS. Results were analyzed using the Kolmogorov-Smirnov, ANOVA, and Tamhane tests (α=.05). ResultsThe MICs of ZnO-NPs and terpenes against S mutans were 61.94 μg/g and 0.25% v/v, respectively. The DCI assay under the cylinders of cement (area of contact with the agar surface) revealed significant bacterial growth inhibition on Temp-Bond NE specimens with ZnO-NPs at MIC of 495.2 μg/g (8× MIC) and with terpenes at MIC 0.999% v/v (4× MIC) (P<.05). The Temp-Bond NE cement cylinder (control group) showed the lowest DTS (1.05 ±0.27 MPa) of all other test groups. In the Zn-NPs group, the greatest increase occurred in the NP8 (8× MIC; 495.2 μg/g) group with a value of 1.50 ±0.23 MPa, a significant increase in DTS compared with the control and terpene groups (P<.05). In the terpene group, the highest increase corresponded to group T2 (2× MIC; 0.4995% v/v) with a value of 1.29 ±0.18 MPa. ConclusionsThe addition of terpenes and ZnO-NPs to interim cement showed antibacterial activity when in contact with S. mutans ATCC 25175. Both terpenes and ZnO-NPs antimicrobial agents increased diametral tensile strength.

Aluminum Oxide Sandblasting of Hexagonal Coping and Abutment: Influence on Retention and Marginal Leakage Using Temporary Cements.

To compare the tensile strength and marginal leakage of prefabricated abutments/copings, with or without surface sandblasting with aluminum oxide, luted with a calcium hydroxide-based temporary cement (CH, Dycal; Dentsply, Petrópolis, RJ, Brazil) or a noneugenol zinc oxide cement (ZO, Temp Bond NE; Kerr, Orange, CA). A total of 48 CeraOne abutment analogs and respective copings were divided into 6 groups (n = 8) according to the component that was sandblasted: the coping only, coping + abutment or no sandblasting and the temporary cement used: CH or ZO. After cementation, the samples underwent 500 thermal cycles (5°C ± 2°C and 55°C ± 2°C) and were subsequently immersed in an aqueous solution of 0.5% basic fuchsine dye for 24 hours. Next, the tensile test was performed, and microleakage was assessed qualitatively. Data were analyzed using Mann-Whitney, Kruskal-Wallis tests, followed by the Student-Newman-Keuls test (α = 0.05). CH cement showed a tensile strength (245.6 N) significantly higher than that of the ZO (18.1 N). Sandblasting both abutment and coping increased tensile strength by 1.7 times. Marginal leakage was not influenced by sandblasting; however, CH presented less microleakage. Aluminum oxide sandblasting of the coping and abutment favored the tensile strength of temporary cements and the CH showed a higher tensile strength and less microleakage than did the ZO cement.

Influence of abutment design on retention of metal copings cemented to implants

Objective The study evaluated the influence of abutment design on the retention of implant-cemented metal copings.Material and methods Two abutments of the same system with the same indications, height and the total occlusal convergence, but of different designs were evaluated. Ten RN synOcta abutments (Straumann, Waltham, MA) and ten RN titanium solid abutments (Straumann, Waltham, MA) were tightened to 35 Ncm on 20 implant analogs previously placed in resin blocks. Twenty plastic burnout copings were waxed, included, cast and machined by a single operator. Coping was inspected for surface irregularities using a stereomicroscope at 10x magnification, and then, they were cemented (Temp Bond NE, Kerr, Romulus, MI) with 5 kg load for 10 min. The samples were stored for 24 h in room temperature and 100% humidity and then subjected to pull-out test at a crosshead speed of 0.5 mm/min. The load required to dislodge each coping was recorded (kgf) and and mean values for each group statistically calculated. Means and standard deviations of loads at failure were analyzed using Student’s t-test.Results The mean load required to dislodge the copings showed by synOcta abutments (11.19 kgf) was statiscally higher than s solid abutments (10.18 kgf).Conclusions: It was concluded that the abutment design influenced significantly the retention of metal copings.