Assessment of a highly-filled flowable composite for the repair of indirect composites.

PURPOSE: To compare the shear-bond-strength (SBS) of a highly-filled-flowable composite (HFFC) and a paste-type composite for indirect composite repair and to evaluate the effect of different surface treatments (ST), concerning the composite repair protocol. METHODS: Eighty-four 5 × 5 × 2 mm cylindrical specimens were prepared using Gradia Plus and SR Nexco indirect composite materials. The samples were thermocycled 5,000 times. According to the ST, the samples were divided into three groups (control, bur, and air-abrasion). After ST, the sample subgroups were divided into two sub-groups according to the repair material: paste-type composite and HFFC (n = 7). Another 5,000 cycles of aging were performed. SBS values were measured with a universal testing machine (Shimadzu, Japan). Shapiro-Wilk, 3-way ANOVA, and Tukey HSD test were used to evaluate data (P < 0.05). RESULTS: ST was considered significant for SBS (P < 0.001). The mean values were (13.9 ± 5.7), (17.0 ± 6.4), (20.4 ± 4.9) MPa for the control, bur and phosphoric acid, and air-abrasion groups, respectively. The surface treatment and repair material interaction was considered significant for SBS (P = 0.044). The highest mean bond strength (24.5 ± 4.5 MPa) was observed for the interaction of SR Nexco, air-abrasion ST, and HFFC repair. CONCLUSION: Repairing with HFFC following air abrasion might enhance the SBS for indirect composite restorations.

Adhesive Performance Assessment of Universal Adhesives and Universal Adhesive/Composite Cement Combinations.

PURPOSE: To investigate the bonding performance of three universal adhesives (UAs) to dentin and the effect of different curing modes and hydrofluoric-acid (HF) etching of lithium-disilicate glass-ceramic on the adhesive performance of two UA/composite cement (CC) combinations. MATERIALS AND METHODS: In the first project part, the immediate and aged (25k and 50k thermocycles) microtensile bond strength (µTBS) of the two light-curing UAs G2-Bond Universal (G2B; GC) and Scotchbond Universal Plus (SBUp; 3M Oral Care), and the self-curing UA Tokuyama Universal Bond II (TUBII; Tokuyama) to flat dentin was measured, when applied in both E&R and SE bonding mode using a split-tooth design (n = 10). The resultant adhesive-dentin interfaces were characterized using TEM. In the second project part, CAD/CAM composite blocks were luted to flat dentin with either Scotchbond Universal Plus/RelyX Universal (SBUp/RxU; 3M Oral Care) or Tokuyama Universal Bond II/Estecem II Plus (TUBII/ECIIp; Tokuyama Dental) using different curing modes (AA mode: auto-curing of both adhesive and cement; AL mode: auto-curing of adhesive and light-curing of cement), upon which their immediate and aged (25k and 50k thermocycles) µTBS was measured. In the third project part, the same UA/CC combinations were luted to CAD/CAM glass-ceramic to measure their immediate and aged (6-month water storage) shear bond strength (SBS). RESULTS: In E&R bonding mode, the performance of G2B, SBUp and TUBII was not significantly different in terms of µTBS, while G2B and SBUp significantly outperformed TUBII in SE bonding mode. No significant difference in µTBS was found between the SBUp/RxU and TUBII/ECIIp UA/CC combinations, regardless of bonding mode, aging time, or curing mode. The cement-curing mode did not significantly influence µTBS, while a significantly higher µTBS was recorded for the UA/CC combinations applied in E&R bonding mode. HF significantly improved the SBS of the UA/CC combinations to glass-ceramic. CONCLUSION: The self-curing adhesive performed better when applied in E&R than in SE bonding mode. The curing mode did not influence the adhesive performance of the composite cements, while an E&R bonding mode rendered more favorable adhesion in a self-curing luting protocol. When bonding to glass-ceramic, the adhesive performance of the universal adhesive/composite cement combinations benefited from HF etching.

Comparison of bracket bonding between two CAD/CAM guided bonding devices: GBD-U vs GBD-B.

OBJECTIVE: To compare the bracket bonding accuracy, efficiency, reproducibility, and three-dimensional (3D) printing duration of the computer-aided design/computer-aided manufacturing (CAD/CAM) unilateral contact guided bonding device (GBD-U) and the bilateral contact guided bonding device (GBD-B) in vitro. METHODS: Five resin dental model sets were scanned and virtually bonded with brackets. GBD-U and GBD-B were designed and 3D printed for each model. GBD-Us had guide blocks that fit the occlusal sides of the bracket tie-wings, while GBD-Bs had guide arms that fit the occlusal and distal sides of the tie-wings. Five orthodontic residents were recruited to bond brackets on the same 3D-printed copies of resin models in a dental mannequin using GBD-Us and GBD-Bs, respectively. The time for 3D printing of GBDs and bracket bonding was recorded. The linear and angular deviations between the bonded brackets and the virtually bonded ones were measured. RESULTS: A total of 50 sets of resin models (1000 brackets/tubes) were bonded. The time for 3D printing and bracket bonding was shorter for GBD-Us (41.96 mins/6.38 mins) than for GBD-Bs (78.04 mins/7.20 mins). In both devices, 100% linear deviations and over 95% angular deviations were below 0.5 mm or 2°, respectively. Deviations in the mesiodistal dimension, torque, angulation, and rotation were significantly lower in the GBD-U group (P<0.01). High inter-operator reproducibility of bracket bonding was confirmed for both devices. CONCLUSION: GBD-U was more time-efficient in 3D printing. Both GBDs showed clinically acceptable accuracy, whereas GBD-U had higher bonding accuracy in the mesiodistal dimension, torque, angulation, and rotation than GBD-B. CLINICAL SIGNIFICANCE: CAD/CAM GBD-U provides high bracket bonding accuracy in a time-efficient manner and has the potential to be clinically applied.

Reliability of qualitative and quantitative assessment of adhesive remnants after debonding of ceramic brackets bonded with Transbond™XT on human molar teeth: An in vitro study.

OBJECTIVE: To test the hypothesis that there are any differences between qualitative and quantitative methods of adhesive remnants index (ARI) scores on the buccal surfaces of the upper molar. MATERIALS AND METHODS: The study included 34 upper first human molars. After etching for 20seconds by using 35% orthophosphoric acid (Ultra-Etch, Ultradent Products Inc., USA) and then rinsed with distilled water for 15seconds, the adhesive (Transbond™XT, 3M™, USA) was applied and cured with the polymerization lamp (Bluephase Style, Ivoclar Vivadent, Liechtenstein) for 10seconds. Ceramic brackets (Damon® Clear™, Ormco, USA) were placed by composite (Transbond™XT, 3M™, USA) on the buccal surface of the molars. Following 24-hour storage of the samples in distilled water (WB-12, Phoenix Instrument, Gabsen, Germany) at 37°C, the brackets were debonded using a debonding plier (Damon Clear Debonding Plier, Ormco, USA). ARI and a modified ARI-scoring system were used. Three independent observers scored the ARI with the naked eye under 10x, 20x, and 32x magnifications using Stereomicroscope Stemi DV4 (Zeiss, Germany). Afterward, the digital microscope VHX-5000 (Keyence, Japan) under 50x magnification was used for the quantitative analysis of the adhesive remnants by just one evaluator. The Fleiss' Kappa-coefficient test was used to assess interrupter reliability. RESULTS: Fleiss' Kappa-coefficient test show that the highest amount of agreement between observers is observed using the naked eye for both of the scoring methods P<0.001. Increasing the magnification led to the moderate decrease of inter-observer agreement. For evaluations with naked eye, a higher agreement is observed for the modified ARI score compared to the ARI scored. The agreement between the quantitative and qualitative evaluation of the ARI score rose with increasing magnification. CONCLUSION: The assessment of adhesive remnants should be done either with naked eye or under 10x magnification, as they showed the highest rate of intra-observer agreement.

Comparative Assessment of pH and Degree of Surface Roughness of Enamel When Etched with Five Commercially Available Etchants: An In Vitro Study.

AIM: To evaluate the pH and degree of surface roughness caused by five commercially and readily available etchants on tooth enamel. MATERIALS AND METHODS: Five different etchants were chosen. An electric pH meter was utilized to test the pH of the etchants employed. Fifteen maxillary bicuspids that had been extracted were cleansed and stored in thymol solution. The samples were sorted into five groups of three each. A noncontact profilometer was employed to assess the microsurface changes of the pre-etched enamel. The teeth were then etched for 30 seconds with respect to the group to which they belonged before being cleaned and dried. The surface roughness after etching was analyzed, measured and values were tabulated. Descriptive statistics and paired t-test were done. RESULTS: The pH of the etchants and surface roughness of the enamel are varied across the five groups, though they have the same composition of 37% orthophosphoric acid. Etchant from Group C was found to be most acidic while the one manufactured by Group E was least acidic. Ivoclar, DPI, and DTECH showed a statistically significant value in surface roughness parameter post-etching (p <0.05). A statistical difference that was significant was observed with the Kruskal-Wallis test for surface roughness parameter (p <0.05). CONCLUSION: All five etchants had varied pH and the amount of surface roughness was also varied though the composition was the same. Further elemental analysis of these etchants has to be done to validate the results obtained. CLINICAL SIGNIFICANCE: Etchants of the same composition should ideally produce the same effect on the tooth enamel surface, but etchants from different manufacturers produce different levels of surface roughness which could be due to differences in the composition of the prepared etchant. The study was conducted to assist in making an educated selection about the most cost-effective but efficient etchant for clinical application.

Clinical assessment of resin-coating technique applied to exposed dentin after crown preparation.

The resin-coating technique, in which exposed dentin surfaces are covered using a thin-film coating material, was approved in the Japanese public health insurance system in December 2019. The purpose of this study was to evaluate clinical cases treated using the resin-coating technique with Hybrid Coat II (HC II) after tooth preparation on vital teeth. A total of 134 cases from patients who visited nine dental clinics were examined from the clinical records. Clinical signs and symptoms of cases before, during, and after treatment and at the time of recall were evaluated. The resin-coating was applied as either a single application with HC II (86.6%) or a combined application of HC II and a flowable resin composite (13.4%). The success rate without any symptoms of sensivity to cold water was 92.5% (124 cases). The current results indicated that the resin-coating with HC II is a reliable treatment for the tooth preparation of vital teeth.

Digital assessment of direct and virtual indirect bonding of orthodontic brackets: A clinical prospective cross-sectional comparative investigation.

OBJECTIVE: The objective of this report is to use in orthodontic patients the methods of virtual indirect bonding and direct bonding using eye vision or loupes in order to compare their accuracy in the three dimensions of space. MATERIAL AND METHODS: Brackets were directly placed by one clinician to 18 patients with a total number of 298 permanent teeth. Then loupes were used to improve bracket positioning. Intraoral scanning of the dental arches was performed before bonding, after direct bonding and after the use of loupes. Subsequently, an orthodontic software was used to virtually indirectly bond the brackets on the first intraoral scanning taken before bonding. A three-dimensional mesh processing software was used to superimpose the three scans and to perform measurements in the mesio-distal and occlusal-gingival dimensions as well as in the mesio-distal angulation. RESULTS: Virtual indirect bonding was more accurate in bracket positioning compared to direct bonding by eye vision or using loupes in all teeth and most of the teeth groups measured. Specific teeth and locations in the dental arch areas exhibited more bonding inaccuracies in the two direct bonding groups as compared to virtual indirect bonding. The use of loupes did not significantly increase the bonding accuracy compared to direct vision. CONCLUSION: Indirect virtual bonding facilitated accurate bracket positioning compared to direct vision or with loupes direct bonding in the dimensions and angulation measured.

Assessment of microcracks and shear bond strength after debonding orthodontic ceramic brackets on enamel priorly etched by different Er,Cr:YSGG and Er:YAG laser settings without acid application: An in vitro study.

BACKGROUND DATA: Enamel microcrack formation has a high incidence after mechanical debonding of ceramic brackets. This may be due to high delivered shear bond strength values when enamel is priorly etched by phosphoric acid. It is still not well elucidated in the literature if laser etching affects enamel the same way. The aim of the research was to analyze different Er,Cr:YSGG and Er:YAG laser etching settings as an alternative to phosphoric acid, in an attempt to prevent enamel microcrack formation during laser etching and mechanical debonding, while reducing the shear bond strength to the minimal clinical acceptable value. MATERIALS AND METHODS: One hundred and thirty-three teeth were randomly divided into 7 experimental groups according to their etching modalities. Settings used for enamel etching were in Er,Cr:YSGG groups: Er,Cr:YSGG (1.5Watt, W/20Hertz, Hz); Er,Cr:YSGG (1.5W/15Hz) and Er,Cr:YSGG (2W/20Hz) and settings used for enamel etching in Er:YAG groups were: Er:YAG (60 millijoules, mJ), Er:YAG (80mJ) and Er:YAG (100mJ). Group C etched with 37% phosphoric acid served as control. Microscopic analysis was performed to assess presence of enamel microcracks. Shear bond strength was evaluated after thermocycling using Weibull survival analysis. RESULTS: All groups showed a reduction in additional microcracks after debonding when compared to control, but only group Er:YAG (60mJ) exhibited a statistically significant difference. Groups Er:YAG (80mJ), control and Er:YAG (100mJ) showed respectively the highest probability of survival at various stress levels followed by groups Er:YAG (60mJ); Er,Cr:YSGG (1.5W/15Hz); Er,Cr:YSGG (2W/20Hz) and Er,Cr:YSGG (1.5W/20Hz) that presented a relatively considerable risk of failure, even at low stress levels. CONCLUSIONS: When considering reduction of enamel microcrack formation and clinical acceptable shear bond strength, none of the groups succeeded both. Etching by Er:YAG (60mJ) and Er,Cr:YSGG (1.5W/15Hz), showed the least overall microcrack incidence between groups, but Er:YAG (60mJ) displayed significant reduction compared to phosphoric acid. However, etching by Er:YAG (80mJ) had the most predictable results in term of shear bond strength.

Comparative assessment of bonding time and 1-year bracket survival using flash-free and conventional adhesives for orthodontic bracket bonding: A split-mouth randomized controlled clinical trial.

INTRODUCTION: A new flash-free adhesive promises to eliminate the flash removal step in bonding and to reduce bonding time by as much as 40% per bracket, with a bond failure rate of less than 2%. The aim of this trial was to compare bonding time and bracket failure rate over a 1-year period between the flash-free adhesive and a conventional adhesive for orthodontic bracket bonding. METHODS: Forty-five consecutive patients had their maxillary incisors, canines, and premolars bonded with ceramic brackets (Clarity Advanced; 3M Unitek, Monrovia, Calif) using a flash-free adhesive (APC Flash-Free Adhesive Appliance System; 3M Unitek) on 1 side and a conventional adhesive (APCII Adhesive Appliance System; 3M Unitek) on the other side. The side allocation was randomized. Bonding was timed to the nearest second. Bond failure was recorded at standardized intervals of 4 weeks. The primary outcome was bonding time (average per tooth for each patient and per quadrant). Secondary outcomes were bracket failure rate within 1 year, time to first-time failure of a bracket, and bond failure type (adhesive remnant index score). Bonding times and adhesive remnant index scores upon bond failure were compared using paired t tests, with P <0.05 considered statistically significant. The adhesives were considered equivalent if the confidence interval for the difference between bracket failure rates fell within a margin of equivalence of ±5%. RESULTS: The bonding times were significantly shorter with the flash-free adhesive than with the conventional adhesive, both per tooth (P <0.001) and per quadrant (P <0.001). Compared with the conventional adhesive, the average bonding times per tooth and per quadrant with the flash-free adhesive were 37.3% and 32.9% shorter, respectively. The bracket failure rates at 1 year were 3.7% for the flash-free adhesive and 0.9% for the conventional adhesive. This was statistically equivalent. The average times to first-time failure of a bracket were 25 weeks for the flash-free adhesive and 11 weeks for the conventional adhesive. Although there were no significant differences in the adhesive remnant index scores upon failure (P >0.05), the flash-free adhesive tended to fail more often at the enamel-adhesive interface than did the conventional adhesive. CONCLUSIONS: The use of the flash-free adhesive may result in bonding time savings of approximately one third compared with the conventional adhesive. With regard to bracket survival, a statistically significant difference was not found between the 2 adhesives when ceramic brackets were bonded. REGISTRATION: This trial was registered on December 3, 2013 (ClinicalTrials.gov ID, NCT02030002). PROTOCOL: The protocol was not published before trial commencement.

Assessment of Shear Bond Strength and Marginal Sealing Ability of Pit and Fissure Sealants: An in vitro Study.

AIM: The aim of the present study was to compare the shear bond strength and marginal sealing ability of self-adhering flow-able composite and conventional fissure sealant. MATERIALS AND METHODS: The samples consisted of 30 healthy premolar teeth which were extracted due to orthodontic reasons and randomly divided into two groups of 15, i.e., group I (Fissurit F) and group II (Dyad Flow). Shear bond strength and marginal sealing ability of both the groups were evaluated in Statistical Package for the Social Sciences (SPSS) version 16. RESULTS: The mean shear bond strength of Dyad Flow (group II) was found to be 1.4 ± 0.87 MPa and in Fissurit F (group I), it was 1.3 ± 1.4 MPa. Differences between the groups were statistically significant. In group II, 53.3% of specimens demonstrated score 0; 33.3% showed score 1; and 13.3% showed score 2. In group I, scores 0 and 1 showed 33.3% of dye penetration respectively. Scores 2 and 3 demonstrated 26.6 and 6.6% of dye penetration respectively. But there was no significant difference between both the sealant groups. CONCLUSION: The present study concluded that self-adhering flowable composite was found to have better shear bond strength and marginal sealing ability than conventional fissure sealant. CLINICAL SIGNIFICANCE: Self-adhering flowable composite can be effectively used in pediatric patients in whom isolation is difficult and exclusion of bonding agent leads to decrease in time consumption.

Comparative assessment of treatment efficacy and adverse effects during nonextraction orthodontic treatment of Class I malocclusion patients with direct and indirect bonding: A parallel randomized clinical trial.

INTRODUCTION: The objective of this 2-arm parallel trial was to compare the effects of direct and indirect bonding techniques on the orthodontic treatment process and outcomes. METHODS: Thirty patients were randomly assigned to undergo bonding of brackets indirectly (group A, n = 15) or directly (group B, n = 15). Eligibility criteria included permanent dentition with bilateral Angle Class I molar and canine relationships, no previous orthodontic treatment, no skeletal discrepancy, and mild or moderate crowding. The main outcome was the orthodontic treatment results assessed using the American Board of Orthodontics Objective Grading System; the secondary outcomes were times taken to perform the laboratory and clinical steps, total treatment duration, plaque accumulation, formation of white spot lesions, bond failures, and need for additional archwire bending and bracket repositioning. The randomization sequence was created using an online randomization software. The patients were allocated with a 1:1 ratio using a block size of 4. The sequence generator was contacted by phone for group assignment after a patient was enrolled for allocation concealment. Blinding was implemented during the dental cast and radiographic evaluations, data entry, and data analysis. Patients were evaluated before treatment, and 1, 2, and 6 months after the start of treatment, and at the end of treatment. RESULTS: All patients completed the study and were analyzed. There were no dropouts. Marginal ridge (median difference, -1.000; 95% confidence interval [CI], -2.99 to -0.001; P = 0.03) and total Objective Grading System scores (median difference, -3.999; 95% CI, -6.000 to -0.005; P = 0.03) were significantly higher in group B than in group A; other Objective Grading System categories did not differ significantly between the groups. The clinical time was significantly longer in group B than in group A (mean difference, -26.51; 95% CI, -29.57 to -23.46; P <0.001), and the total time was significantly longer in group A than in group B (mean difference, 19.03; 95% CI, 15.32 to 22.74; P <0.001). There were no significant between-group differences in treatment duration, plaque accumulation, formation of white spot lesions, bond failure, or need for additional archwire bending or bracket repositioning. No harms were encountered. CONCLUSIONS: Indirect bonding was significantly faster than direct bonding in the clinical stage and yielded better marginal ridge and total scores. Both techniques showed similar rates of plaque accumulation, formation of white spot lesions, bond failure, and additional archwire bending and bracket repositioning. REGISTRATION: The trial was not registered. PROTOCOL: The protocol was not published before trial commencement.

Comparative assessment of the efficacy of closed helical loop and T-loop for space closure in lingual orthodontics-a finite element study.

BACKGROUND: Retraction in lingual orthodontics has biomechanical differences when compared to labial orthodontics, which is not yet established. Thus, we have intended to compare the biomechanical characteristics of closed helical loop and T-loop on 1 mm activation with 30° of compensatory curvatures during retraction in lingual orthodontics. METHODS: STb lingual brackets were indirectly bonded to maxillary typhodont model that was scanned to obtain FEM model. Closed helical loop (2 × 7 mm) and T-loop (6 × 2 × 7 mm) of 0.016″ × 0.016″ TMA wire were modeled without preactivation bends. Preactivation bends at 30° were given in the software. Boundary conditions were set. The force (F) and moment (M) of both the loops were determined on 1 mm activation, using ANSYS software. M/F ratio was also calculated for both the loops. RESULTS: T-loop exerted less force, thus increased M/F ratio as compared to closed helical loop on 1 mm activation. CONCLUSIONS: When torque has to be preserved in the anterior segment during retraction in lingual orthodontics, T-loop can be preferred over closed helical loop.

Assessment of Fracture Resistance Capacity of Different Core Materials with Porcelain Fused to Metal Crown: An in vitro Study.

Aim: The aim of the study was to evaluate the capacity to resist fracture in different core buildup materials with porcelain fused to metal (PFM) crown. Materials and methods: Totally, 45 mandibular single rooted first premolars were collected, which were sound along with similar shape and size. The teeth were sectioned at 15 mm above the root apex sparing the sound tooth structure. The teeth were endodontically treated with the crown-down technique using nickel-titanium (NiTi) instrumentation. The specimens were randomized into three groups as per the core materials used and were labeled accordingly. Group I consisted of dual-cured composite resin, group II consisted of glass ionomer reinforced with resin, and group III consisted of Miracle mix. Universal loading machine is used for measuring the compres-sive load applied to fracture the tooth. Results: The mean value of compressive strength was maximum in the dual cured composite resin (598.42 ± 22.64) followed by glass ionomer reinforced with resin (478.88 ± 26.74) and Miracle mix (442.16 ± 30.10). The results showed a significant difference statistically within the core materials used with p < 0.05. The results from the Tukey's post hoc test of multiple comparisons between dual-cured composite resin vs glass ionomer reinforced with resin, dual-cured composite resin vs Miracle mix, and glass ionomer reinforced with resin vs Miracle mix showed a highly statistical difference with p < 0.05, which is significant. Conclusion: This in vitro study showed that the dual-cured composite resin had maximum resistance to fracture compared with other core buildup materials on teeth which were endodonti-cally treated. Clinical significance: Restoration of a tooth which is structurally compromised is a tricky job for all the dentists. Restoring it with a proper core buildup material with adequate fracture resistance makes the tooth structure stable. The core material should be able to resist all types of occlusal forces and to distribute it equally within the tooth structure. Keywords: Core buildup, Crowns, Endodontically treated teeth, Fracture resistance.

Evaluation of the relationship between the cost and properties of glass ionomer cements indicated for atraumatic restorative treatment.

The aim of this study was to evaluate microshear bond strength (µSBS), water sorption and solubility of glass ionomer cements (GIC) indicated for atraumatic restorative treatment (ART). Cylindrical specimens (6 x 2.4 mm) were used to test the sorption and solubility of each GIC (n = 5). The specimens were weighed before and after immersion in water and desiccation. For the µSBS test, 60 primary molars were ground to obtain flat surfaces from both enamel and dentin. The teeth were then assigned to the tested GIC (n = 10) groups, namely Fuji IX - FIX, Ketac Molar - KM and Maxxion R - MX. The exposed surfaces were pre-treated with GIC liquid. Polyethylene tubes were placed on the pre-treated surface and filled with one of the GIC. After 24 h, the specimens were submitted to the µSBS test. The failure mode was assessed using a stereomicroscope (400 x magnification). The powder to liquid ratio and cost of material were also determined (n = 3). The data were analyzed by ANOVA and Tukey's post hoc test. Linear regression was used to determine the relation between cost and the other variables. Overall, MX showed lower µSBS values (enamel: 3.93 ± 0.38; dentin: 5.04 ± 0.70) than FIX (enamel: 5.95 ± 0.85; dentin: 7.01 ± 1.06) and KM (enamel: 5.91 ± 0.78; dentin: 6.88 ± 1.35), as well as higher sorption and solubility. The regression analyses showed a significant and positive correlation between cost and µSBS in enamel (R2 = 0.62; p < 0.001) and dentin (R2 = 0.43; p < 0.001); and a negative correlation between cost and water sorption (R2 = 0.93; p < 0.001) and solubility (R2 = 0.79; p < 0.001). In conclusion, the materials indicated for ART exhibit distinct physical and mechanical properties; in addition, low-priced materials may interfere with GIC properties.

Evaluation of the relationship between the cost and properties of glass ionomer cements indicated for atraumatic restorative treatment

The aim of this study was to evaluate microshear bond strength (μSBS), water sorption and solubility of glass ionomer cements (GIC) indicated for atraumatic restorative treatment (ART). Cylindrical specimens (6x2.4 mm) were used to test the sorption and solubility of each GIC (n = 5). The specimens were weighed before and after immersion in water and desiccation. For the μSBS test, 60 primary molars were ground to obtain flat surfaces from both enamel and dentin. The teeth were then assigned to the tested GIC (n = 10) groups, namely Fuji IX - FIX, Ketac Molar - KM and Maxxion R – MX. The exposed surfaces were pre-treated with GIC liquid. Polyethylene tubes were placed on the pre-treated surface and filled with one of the GIC. After 24 h, the specimens were submitted to the μSBS test. The failure mode was assessed using a stereomicroscope (400x magnification). The powder to liquid ratio and cost of material were also determined (n = 3). The data were analyzed by ANOVA and Tukey's post hoc test. Linear regression was used to determine the relation between cost and the other variables. Overall, MX showed lower μSBS values (enamel: 3.93 ± 0.38; dentin: 5.04 ± 0.70) than FIX (enamel: 5.95 ± 0.85; dentin: 7.01 ± 1.06) and KM (enamel: 5.91 ± 0.78; dentin: 6.88 ± 1.35), as well as higher sorption and solubility. The regression analyses showed a significant and positive correlation between cost and μSBS in enamel (R2 = 0.62; p < 0.001) and dentin (R2 = 0.43; p < 0.001); and a negative correlation between cost and water sorption (R2 = 0.93; p < 0.001) and solubility (R2 = 0.79; p < 0.001). In conclusion, the materials indicated for ART exhibit distinct physical and mechanical properties; in addition, low-priced materials may interfere with GIC properties.

Technique Tips--The Cost of One Post-Operative Sensitivity following Placement of a Posterior Composite Restoration.

Use a low shrinkage stress composite but, if not, use incremental placement and a layer of flowable at the gingival box; Ensure good bonding to dentine and enamel and avoid (over) etching the dentine; Ensure good adaptation at the gingival floor of a Class II box; Make sure that the restoration has received sufficient light; Provide good isolation; Use reliable and tested materials throughout.

Fibre-reinforced composite (FRC) bridge--a minimally destructive approach.

Replacing missing teeth is an integral part of the clinical services of the dental practitioner. The fibre-reinforced composite (FRC) bridge is a relatively new method for replacing missing teeth. This article will explain and discuss this alternative treatment option. Practical instructions on how to construct a FRC bridge will be given, by means of a clinical case. Different technique options will be illustrated to provide the reader with a good understanding of the most practical way to use the FRC strips. The fibre-reinforced composite provides a non-destructive, aesthetically pleasing and cost-effective way to restore missing teeth. Clinical Relevance: Minimally invasive options should always be considered and destruction of healthy enamel and dentine during the preparation phase of a replacement treatment should be avoided as much as possible.