Diamond Bur Research Articles

A Comparative Study of Cervical Composite Restorations Microleakage Using Dental Universal Bonding and Two-step Self-etch Adhesive

The aim of this study is to compare microleakage of cervical restorations using universal bonding and two-step self-etch adhesive with or without enamel etching through a dye penetration testing method. In this in vitro experimental study, 70 maxillary premolar teeth with no anomaly or decay were randomly divided into five groups of 14. Conventional cervical cavities were prepared with diamond bur on the facial surface of the teeth. The teeth were prepared using G-Premio Bond/self-etch technique, G-Premio Bond/total-etch technique, G-Premio Bond/selective-etch technique, Clearfil SE Bond/self-etch technique, and Clearfil SE Bond/selective-etch technique in Groups I to V, respectively, and restored with composite. Microleakage at the occlusal enamel margin and the cervical dentinal margin was ranked from 0 to 4 based on dye penetration using stereomicroscope (×32). Statistical analysis was carried out using Kruskal-Wallis and Mann-Whitney tests at a significance level of α = 0.05. The mean occlusal microleakage in the five study groups was 1.07, 0.57, 0.57, 1.28, and 0.78, respectively. The mean cervical microleakage was 0.97, 0.85, 0.64, 1.35, and 1.14, respectively. Kruskal-Wallis test showed significant difference between the microleakage scores of different groups in enamel (p = 0.022) and dentin (p = 0.01). Clearfil SE Bond/self-etch technique group showed the highest mean score of microleakage in enamel margins, and G-Premio Bond/total-etch technique and G-Premio Bond/selective-etch technique groups showed lowest enamel microleakage mean. Clearfil SE Bond/self-etch group showed the highest mean score of microleakage in dentin margins, while G-Premio Bond/selective-etch technique group showed the lowest mean score of dentin microleakage. Selective etching of enamel will decrease enamel microleakage. G-Premio Bond shows better microleakage results in comparison to Clearfil SE Bond in dentinal margins. A major problem in cervical composite restorations is the presence of microleakage in the cervical wall. Different adhesive systems have been designed to overcome this problem.

Gingival Depigmentation

Gingival hyperpigmentation is the condition where melanin deposition occurs in the suprabasal cell layers of the gingival epithelium. Gingival hyperpigmentation is a multifactorial benign condition which causes esthetic concern to the person. Melanin is a nonhemoglobin-derived pigment formed by melanocytes, which are dendritic cells of neuroectodermal origin in the basal and spinous layers. Melanin is a brown-colored pigment, and it is the result of endogenous pigmentation. The deposition of melanin pigment darkens the color of the gingiva. Many individuals visit the dentist or periodontist to seek the treatment of hyperpigmentation of the gingiva. Gingival pigmentation is usually considered as a genetic factor and affects different races differently. Various treatment modalities are available to remove gingival hyperpigmentation which includes scalpel technique, abrasion using diamond bur, laser therapy, electrosurgery, cryotherapy, chemical cauterization, depigmentation followed by gingival autografts, or platelet-rich fibrin. The present case report describes the case of gingival hyperpigmentation managed by scalpel technique and abrasions by diamond bur which is a simple and a cost-effective technique with satisfactory results.

Comparative Evaluation of Dentin Surface after Preparation by Diamond Bur and Oscillating Tip, with and without Etching

Objective: Oscillating ultrasonic instruments were basically used to finish marginal preparation, while they produce more rough surfaces, unlike the regular surfaces produced by the rotating diamond instruments. This study aims to investigate the change of dentin roughness after etching using two different preparation tools: diamond bur and diamond ultrasonic tip. Materials & Methods:Two groups of dentin surfaces related to extracted premolars were considered: the first group consisted from 13 surfaces prepared with a Rotating Diamond Bur (RB-P), the second group consisted of 13 surfaces prepared with oscillating tip (O-P). For all surfaces, the roughness were measured using an optical profilometer microscope once after preparation and thereafter etching with phosphoric acid (35%) for 20 seconds. Two samples were imaged under scanning electronic microscope SEM only after the preparation. Surface roughness RMS, Developed Interfacial Area Ration (Sdr) and Surface Development were compared using 1-way ANOVA test, Kruskal-Wallis and ANOVA for Ranks test, respectively. Results & Discussion: Preparation with oscillating tip produced the highest value of roughness (O-P: 3.22 ± 0.73), while there was difference in roughness after the etching procedure (E_O-P: 2.27 ± 0.262) at P_value = 0.046 < 0.05. The etching procedure did not result a valuable change in the roughness in the Rotating Bur Preparation group before (RB-P: 2.72 ± 0.41) and after etching (E_RB-P: 2.39 ± 0.42) at P_value = 0.514 > 0.05. SEM images shows more irregular surface with deeper grooves on the dentinal surface in the O-P group. The highest value of Sdr is associated with the O-P group (0.71± 0.14) resulting the best adhesion. Conclusion: Etching the dentin surface with phosphoric acid affected the roughness. The effect was more noticeable when the surface is prepared with oscillating ultra-sonic tip. The choice of the preparation tool should depend only which tool is the least traumatic instrument for the marginal periodontal tissues.

Evaluation of Sealing Ability of Biodentine to Root-End Cavities Irrigated either with Maleic Acid or Irritrol Using Glucose Filtration Model

Objective: To compare the effect of Maleic acid and Irritrol (combination of Chlorhexidine & Ethylenediaminetetraacetic acid) irrigation on the sealing ability of Biodentine when used as root-end filling material . Material and Methods: Thirty single-rooted human premolars were subjected to standardized root canal instrumentation and were irrigated with 2.5% Sodium Hypochlorite (NaOCl) after each instrument change. Apical root resections were done by removing 3 mm of the apex at a 90° angle to the long axis of the root with a diamond bur. The root end cavity preparation was done using ultrasonic tips at a low power setting under water coolant. They were randomly divided into 3 groups (n=10). Group 1 was irrigated with 7% Maleic acid, Group 2 was irrigated with Irritrol, and Group 3 was irrigated with 0.9% Saline (Control). Then, the root end cavities of all the samples were restored with Biodentine and were subjected to leakage analysis using a glucose filtration test. The mean values for each group were calculated and the obtained data was statistically analysed using ANOVA with post-hoc Tukey’s test, ANOVA with post-hoc Games-Howell test and repeated measures ANOVA with post-hoc Bonferroni test. Results: The specimens irrigated with Irritrol showed least microleakage as compared to 7% Maleic acid and 0.9% Saline . Conclusion: A regimen involving irrigation of the root-end cavity with Irritrol followed by root-end filling with Biodentine can improve the apical seal.

Minimal intervention in dentistry: which is the best approach for silorane composite restoration repairs?

BackgroundThis study aimed to evaluate surface treatments, adhesives and composites for repairing silorane based restorations. Material and MethodsOne hundred and twenty truncated cones (2 mm smaller diameter and 4 mm larger diameter) made of silorane composite were divided in 12 groups according with the surface treatment (diamond bur and oxide aluminum abrasion), the adhesive (Adper Scothbond Multipurpose (3M ESPE), Ecusit (Voco) and Filtek P90 Adhesive (3M ESPE)). Each group was subdivided in two according with the composite used for repair (methacrylate and silorane). The repair was made with a second truncated cone build over the first one and bond strength assssed by tensile strength. Data were submitted to ANOVA 3-way and Tukey’s test (p<0.05). ResultsThere was difference only for the adhesives and the composites, with conventional adhesives (Adper Scothbond Mutipurpose) and methacrylate-based composites (Filtek Z350) presenting superior tensile strength compared to the silorane ones (P90 Adhesive system and composite). ConclusionsTherefore, it must be concluded that silorane composite can be repaired with methacrylate base composites and adhesives. Key words:Silorane composites, composites, bond strength, minimal intervention.

Comparative evaluation of efficacy of two minimally invasive caries removal techniques on fracture resistance of the teeth restored with composite: An SEM study.

Aim:The aim of the study was to evaluate and compare the efficacy and fracture resistance of the teeth restored with composite using two minimally invasive caries removal techniques under a scanning electron microscope.Materials and Methodology:Forty-five freshly extracted human permanent molars with Class I and II dentinal caries were selected. Diamond bur group (15): The carious lesion was excavated using round diamond bur until hard dentine was detected. Polymer bur group (15): Carious lesion was removed using polymer burs in circular motions. V-cariesolve gel group (15): Carious lesion was covered with V-cariesolve gel for 30 s and was scraped using a spoon excavator. The time required for the caries removal by each group was recorded. The effectiveness of caries excavation was verified using caries indicator dye. The smear layer removal was assessed using a scanning electron microscope. The cavities were restored with composite resin and fracture resistance of teeth was evaluated. All the data were tabulated and analyzed using Kruskal–Wallis test for overall comparison followed by Mann–Whitney U-test for pairwise comparison.Results:The mean time taken for caries excavation by diamond bur group was less (86.13 s), retention of smear layer was less with diamond bur group, and the median score for staining of infected dentin was more (3) in V-cariesolve gel group. Fracture resistance was highest (1.53) with diamond bur group (P < 0.001).Conclusion:Caries removal efficacy and fracture resistance for diamond bur group were better compared to polymer bur group and v-cariesolve gel.

Debonding of Leucite-reinforced Glass-ceramic Veneers Using Er, Cr:YSGG Laser Device: Optimizing Speed with Thermal Safety.

Removing laminate veneers on anterior teeth by using an Er,Cr:YSGG dental laser can be completed faster than previously reported while maintaining thermal safety.

Comparative evaluation of removal of smear layer using newer rotary endodontic files: A scanning electron microscope study

Aim:The aim of this study is to evaluate the smear layer removal efficacy of newer rotary files using scanning electron microscopic analysis at the coronal, middle, and apical third of the root canal.Materials and Methods:In this study, sixty permanent human single-rooted teeth with complete, mature root apices without any anatomic variation having straight patent root canal extracted for periodontal cause were included. The samples were cleaned to remove debris, calculus and rinsed with sodium hypochlorite to remove organic tissue and then stored in distilled water. All the samples were decoronated with the help of carborundum disc at root length of 12 mm to obtain segments similar in length. After this, all the samples were randomly divided into four groups -Protaper universal, Protaper Gold, EDM, and Revo-S. After cleaning and shaping, samples in each group were finally flushed with normal saline. Samples were then dried. Grooves were made into the root in the buccal and lingual portion of the root using a diamond bur and the samples were split longitudinally into two halves using stainless steel chisel and mallet. Preparation for scanning electron microscope was done and phototmicrographs at ×3000 were taken.Result:Chi square test and Kruskal–Wallis test was used for statistical analysis. Result of this study showed that Revo –S was found to be best amongst the groups and EDM was the poorest.Conclusions:Based on the present study, Revo-S files showed the best smear layer removal in the coronal, middle, and apical 1/3rd of the root canal when compared to other groups. Within the parameters of the study, Revo –S was found to be best amongst the groups and EDM was the poorest. The quality of various files according to ranks of smear layer removal was found to be: Group IV > Group II > Group I > Group III.

Repair bond strength of aged resin composite using different surface treatments and bonding protocols

Background: Repair of direct composites are less invasive than replacement, diminishing the risk of iatrogenic exposure of the pulp and the risk of detrimental to adjacent teeth, all in all, reducing the procession of the “restoration death spiral”. Aim: This study aimed to evaluate the repair bond strength of aged resin composites using different surface treatments and bonding protocols. Materials and Methods: A total of 45 discs (n=45) were fabricated of Nanohybrid composite measuring about 2.5 mm in height and 3.5 mm in diameter and were mounted in acrylic resin and subjected to 10,000 thermal cycles between 5-55 ? C with 30 seconds of dwell time in a thermocycler in order to simulate artificial ageing. All these samples were assigned into three groups (n=15) based on the surface treatment protocol. According to the bonding protocol, the samples in each group are further divided into three subgroups (n=5). After surface treatments of the aged composites, the application of bonding agent followed by new composite material was performed. All the samples were stored in distilled water at 37 ? C for 24 hours. The shear bond strength of the samples was measured using a universal testing machine at a crosshead speed of 1mm/min. Results: Among the groups, the mean bond strength in medium grain diamond bur and 37% phosphoric acid etchant with the universal bonding agent subgroup was higher 852.56±27.71 than the remaining groups. The lowest mean bond strength of 200.9±10.62 was observed in 37% Etchant with direct composite subgroup. Conclusion: Different combinations of surface treatments and bonding protocols affect shear bond strength differently. The highest shear bond strength values were achieved for the group where surface treatment was done with the combination of blue diamond bur and 37% phosphoric acid along with a universal bonding agent.

Effects of ultrasonic refinement on endodontic access cavity walls: A microcomputed tomography analysis.

Objectives:The present study aimed in assessing the coronal defects after access cavity finishing and refinement by micro.Methods:Access cavities on thirty molars were prepared using a diamond bur. To finish and refine the access cavity, the Endo-Z was used in group 1 (n=15) and Start X 1 in group 2. Preparation time was recorded. A micro-CT scan was done before and after access preparation. Formation and location of the new defects were registered, the extension of defects calculated and the direction of the extension registered, preparation time and surface roughness determined (P < 0.05).Results:Preparation time was significantly higher with ultrasonics (P <0.001). Internal walls showed smoother surfaces for Endo-Z group. Newly counts and extension length of defects weren't significantly different between groups (P > .05).Conclusion:Ultrasonic tips induced new cracks. Both instruments caused the extension of cracks. Ultrasonic tips requires more time and results in significantly rougher surfaces.

A comparative study on the effect of polishing systems on the color and surface texture of different porcelain systems - feldspathic, pressable, and computer-aided design/computer-aided manufacturing.

Aim:To find and compare the qualitative and quantitative change in color and surface texture of feldspathic ceramic, pressable ceramic and ceramic used in computer-aided design/computer-aided manufacturing CAD/CAM after different surface treatments namely glazing, abrading and polishing. To compare the effectiveness of pearl finish polishing paste and Soflex polishing system used in the study.Setting and Design:In-vitro, comparative study.Materials and Methods:Disc-shaped feldsapathic, pressable, CAD/CAM ceramic specimens were fabricated. Surface roughness and color parameters Δ L*, Δa*, and Δ b* were measured before glazing, after glazing, after abrasion with 02 diamond bur and after polishing with two different polishing systems. Surface roughness was measured qualitatively using scanning electron microscopy and quantitatively using an optical profilometer. The value of color parameters was obtained using a colorimeter. Data were statistically analyzed with ANOVA.Statistical Analysis Used:SPSS software 20.0 version (IBM, New York, United states of America).Results:Unglazed feldspathic, pressable and CAD/CAM porcelain specimens showed a mean surface roughness value of 2.73 ± 0.38, 3.54 ± 1.42, and 3 ± 1.74 specimens. After glazing and polishing, the surface roughness values decreased. After abrasion, surface roughness values increased. Polishing did not alter the color along the red green axis and yellow blue axis.Conclusions:Abraded specimens of feldspathic, pressable and CAD/CAM after polishing using pearl finish polishing paste and Soflex disc became smoother than glazed specimens. When pearl finish polishing paste and Soflex discs were compared for their effectiveness the former appeared to be more superior but not to a significant level. Mechanically altering feldspathic, pressable, and porcelain used in CAD/CAM technology does not cause any change in shade.

Aesthetic Repair of Zirconia-Supported Porcelain Prosthesis with Ceramic Veneer, Case Report with 3-Year Follow-up

Chipping is the most common complication in zirconia-supported porcelain prosthesis. If the prosthesis has ideal adaptation and there is no problem other than chipping, intraoral repair is the most practical solution for such failures. Composite resins are often preferred for intraoral porcelain repair. However, the wear and unstable colour of composite resins negatively affect aesthetics. This complication could be restored intraorally and aesthetically with ceramic veneer. This case report presents the intraoral repair of a zirconia supported Fixed Partial Denture (FPD) consisting of four units. The cohesive fracture of the ceramic material in the incisal part of maxillary right central incisor was restored with ceramic veneers. Preparation was done with a tapered, rounded end diamond bur under water-cooling. The impression was taken with elastomeric impression material. Ceramic veneer was manufactured with a leucite-reinforced glass-ceramic and cemented with light cure resin cement. Based on the three-year follow up of the performed intraoral repair, ceramic veneers have shown to be an alternative treatment for fractured FPD.

Comparison of piezosurgery and conventional rotary instruments in schneider's membrane sinus lifting: A pilot randomized trial.

BackgroundThe present study aimed to evaluate and compare the postoperative effects of the piezoelectric device and conventional rotary instruments in Schneider’s membrane sinus lifting procedure. Material and MethodsTwenty patients requiring bilateral maxillary bone graft augmentation in the posterior maxillary region were selected. Piezoelectric surgery was performed on one side and conventional surgery with a rotary diamond bur on the other. Postoperative pain, swelling, edema, and mouth opening were evaluated at one hour and two and seven days after the procedures. All variables were submitted to Friedman or Wilcoxon tests at a 5% significance level. ResultsThe comparison between groups showed that postoperative pain after one hour and two days was significantly lower (p< 0.05) in the piezoelectric device group. Regarding the edema, the results of both techniques were similar at all times assessed (p> 0.05). Piezosurgery was statistically associated (p< 0.05) with greater mouth opening only at the 48-hour evaluation. ConclusionsOsteotomy with a piezoelectric device causes less pain and greater mouth opening postoperatively compared with the conventional technique. Key words:Piezosurgery, sinus lift, edema, pain, rotative instruments.

Cone Beam Computed Tomography Assessment of the Volume of Dental Tissue Removed During Endodontic Access.

The purpose of this study was to determine the volume of dental tissue removed during endodontic access preparation with cone-beam computed tomography (CBCT) comparing two different software. CBCT images of 20 teeth were obtained before and after endodontic access performed with spherical and conical diamond burs. The images were taken with i-CAT Precise system with 0.25 mm voxel size. Digital Imaging and Communications in Medicine (DICOM) images were loaded on two different software programs (Materialise® and InVersalius®), and a 3D reconstruction of the CBCT images was performed on both programs. The baseline volume (BV), and the final volume (FV) were obtained, and the lost tissue volume (LV) was calculated using the formula: LV=BV-FV. The t-test was used to compare initial and final volumes and also to compare the two programs, using a significance level of 5%. The volumetric data calculated for the Materialise and the InVesalius programs were, respectively: BV-mean of 441.79±85.08 mm3 and 442.01±84.83 mm3; FV-mean of 426.75±83.88 mm3 and 426.94±83.75 mm3; LV-mean of 15.04±4.32 mm3 and 15.07±4.16 mm3. No statistically significant difference was found in the volumes calculated by either program for initial, final, or removed tissue (P>0.05). However, there was a significant difference between the BV and LV calculated on the same program (P<0.05). Our in vitro study showed that CBCT was able to determine the volume of dental tissue removed in the endodontic access preparation of extracted human teeth, regardless of the software program used.

Comparison of the microleakage between two different flowable composite resin restorations with 8th generation bond system in Class II cavity: An in vitro stereomicroscopic study.

Introduction Marginal adaptability of composite resins is one of the prime factors for the success of class II cavity restoration. Materials and Methodology: Forty non-carious extracted mandibular molar with fully formed apices were collected and Class II box type cavities were prepared on both mesial and distal surfaces of every tooth using a new straight fissure diamond bur and high-speed airrotor handpiece. According to the type of restorative materials used, teeth were divided into Group I (n=20): Restored with SDR (Smart Dentin Replacement) and Group II (n=20): Restored with Tetric Eva Flow Bulk Fill. After 24 hours of storage in distilled water at 37˚C, the restored specimens were subjected to artificial aging by thermocycling. The teeth were then immersed in a 2% methylene blue dye for 24 hours. All samples were cut longitudinally through the center of the restorations with the help of an isomet diamond saw. The sections were then observed under a stereomicroscope at 25X for scoring the depth of dye penetration at cervical and axial walls toward the pulp. Results: Mean score of Group Ia is 0.4±0.83 and Ib was 0.55±0.88 respectively while the mean score of Group IIa was 0.75±1.118 and in IIb was 0.75±1.019 respectively. Microleakage was found to be highest in Group IIa and minimum in Group Ia. Conclusion: Use of a flowable composite SDR above and below the CEJ in Class II composite resin restorations showed good results.

Three-Dimensional Surface Evaluation and Shear Bond Strength of Three Pre-treatment E-max Surfaces for Metal and Ceramic Orthodontic Brackets

3D evaluation and shear bond strength (SBS) for metal and ceramic brackets after three pre-treatment surfaces of lithium disilicate (LD) crowns. Sixty lithium disilicate (LD) crowns were fabricated in laboratory according to manufacturer instruction and then divided into six groups (three groups for metal brackets and three groups for ceramic one). The 1st group for both was treated with round diamond bur, the 2nd one by hydrofluoric acid (HFA) 9.0%, and the 3rd group by laser (Er,Cr:YSGG). All treated surfaces were examined by laser profilometer and scan electron microscope. The Scotchbond Universal Adhesive and Transbond XT were used for bracketing procedure for metal and ceramic bracket (central incisor, 0,022” slot). Universal testing machine was used for shear bond. A crosshead speed of 1 mm/min was used, and the maximum load necessary to deboned the bracket will be recorded. HFA treated surfaces gave a highest SBS for both metal and ceramic brackets, then laser and finally the bur. The lowest roughness parameter Sa (arithmetical mean height) was in bur, both laser and HFA gave no significant differences. The HFA gave a highest Sz (maximum height) and Spc (arithmetic mean peak curvature) value. To increase the shear bond strength, the HFA is one of the best methods for roughness although the laser gave nearby roughness parameters. Ceramic brackets gave higher SBS than metal one with all pre-treatment procedures.

Effects of remaining dentin thickness, smear layer and aging on the bond strengths of self-etch adhesives to dentin.

This study evaluated the effects of remaining dentin thickness (RDT), different smear layers, and aging on the microtensile bond strength (µTBS) of universal adhesives to dentin when applied in self-etch mode. Ninety-six human third molars were randomly allocated to 12 groups (n=8) based on adhesives: ClearfilTM SE Bond 2 (SE, control), ClearfilTM Universal Bond (CU) and ScotchBondTM Universal Adhesive (SB); smear layers: prepared either with 600-grit SiC paper (P) or regular diamond bur (B); and aging: stored in distilled water at 37ºC for 24 hours (24h) or 1 year (1y). µTBS was significantly affected by the type of adhesives, smear layers, and aging (p<0.001). A statistically significant and positive linear relationship was also observed between µTBS and RDT (p<0.05) in all the tested groups, except for SEB1y and CUB24h (p>0.05). RDT, smear layer types, and aging can influence the bonding performances of universal adhesives when applied in self-etch mode.

Comparison of the enamel surface roughness before bonding and after debonding by diamond, tungsten carbide and fiber reinforced composite burs under AFM an in-vitro study

Introduction: The bonding of orthodontic attachments directly to etched enamel surface is an example of clinical application of a simplified procedure. With modifications of the acid etch technique and resin systems, the removal of the directly bonded attachments and finishing of the underlying enamel have become an acute clinical problem. Aims and Objectives: To evaluate the enamel surface roughness observed under atomic force microscope (AFM) in following methods: 1. Before bonding; 2. Removal of residual resin after debonding with 3 different burs. Fine diamond bur Tungsten carbide bur Fiber reinforced composite bur Materials and Methods: Sixty premolar teeth were divided into 3 equal groups and the buccal surface were subjected to AFM to obtain Ra, Rq, Rmax initial roughness values. The brackets were bonded with a light-cured adhesive and debonded with posterior debonding plier. Residual resin was removed with different burs in 3 groups respectively and subjected to final AFM measurements. Results of roughness were analysed with the use of repeated measurement analysis of variance and independent t-test respectively. Results: It was found out that parametric values were statistically insignificant with P value >0.001 in prebond condition & statistically significant after resin removal with P value Conclusion: Fiber reinforced composite bur created smoother surface after debonding when compared to diamond and tungsten carbide bur. Keyword: Fine diamond bur, Tungsten carbide bur, Fiber reinforced composite bur, Residual resin, AFM.

Scattering and phase-contrast X-ray methods reveal damage to glass fibers in endodontic posts following dental bur trimming

ObjectivesThere is concern that the integrity of fiberglass dental posts may be affected by chairside trimming during treatment. We hypothesize that hard X-ray methods of phase contrast-enhanced micro-CT (PCE-CT) and synchrotron based X-ray refraction (SXRR) can reliably identify and help characterize the extent of damage. MethodsFiberglass posts were imaged both as manufactured and following trimming with a diamond bur. Each of the posts was imaged by SXRR and by PCE-CT. Datasets from PCE-CT were used to visualize and quantify 2D and 3D morphological characteristics of intact and of damage-affected regions caused by trimming. ResultsThe SXRR images revealed fiber inhomogeneities from manufacturing with a significant increase in internal surfaces in sample regions corresponding to damage from trimming. PCE-CT volumes unveiled the micromorphology of single fibers in the posts and some damage in the trimmed area (e.g. fractures, splinters and cracks). Area, perimeter, circularity, roundness, volume and thickness of the glass fibers in the trimmed area were statistically different from the control (p < 0.01). SignificanceThe integrity of single fibers in the post is critical for bending resistance and for long-term adhesion to the cement in the root canals. Damage to the fibers causes substantial structural weakening across the post diameter. Glass fragments produced due to contact with the dental bur may separate from the post and may significantly reduce bond capacity. The above mentioned synchrotron-based imaging techniques can further facilitate assessment of the structural integrity and the appearance of defects in posts (e.g. after mechanical load).

Effects of Different Polishing Procedures on the Surface Roughness and Hardness of Polyether Ether Ketone (PEEK)

There is insufficient information about the chairside polishing methods of polyether ether ketone material. Therefore, it is aimed in this study to investigate the effects of different polishing processes on polyether ether ketone surface roughness and hardness. A total of 66 disc-shaped specimens made of polyether ether ketone were used in this study. The specimens were polished conventionally and randomly divided into three groups (n=22). One group was designated as the control group, and no further treatment was applied. In the other two groups, the specimens’ surfaces were abraded with diamond burs and polished using two different polishing kits. Their surface roughness and Vickers hardness were measured, and environmental scanning electron microscopy and atomic force microscopy examinations were performed. The data were statistically analysed using analysis of variance and Tukey’s honest significant difference test (α=0.05). There were no statistically significant differences between the control and polishing kit groups in terms of either surface roughness or Vickers hardness (p&gt;0.05). The polishing kits can be used reliably and effectively for polishing polyether ether ketone materials.