Carbide Bur Research Articles

Influence of Operator, Tool, Dental Loupes, and Tooth Position on Enamel Loss and Composite Remnants After Removal of Composite Attachments for Orthodontic Clear Aligners: An Experimental Study Using 3D Profilometry.

To assess the influence of operator, tool, dental loupes, and tooth position on enamel loss and composite remnants after removal of composite attachments (CA) for orthodontic clear aligners. Procedure duration was also analyzed. Eight maxillary resin dental arches with four natural teeth were placed in the right posterior sector in dental simulators, and CA was realized. The dental arches were randomly distributed according to three experimental factors: operator (junior, senior), tool (tungsten carbide bur and silicone polisher, only silicone polishers), and use of dental loupes. Dental arches were scanned with 3D profilometry before and after CA removal to measure enamel surface height variation (ESHV), particularly enamel loss in the CA area. Digital microscopy was used to detect composite remnants. The mean enamel loss was -22.7 ± 29.4 µm (range -132 to 0 µm). It was not significantly influenced by experimental factors or tooth position. Composite remnants were found in 34.4% of teeth, significantly more in senior than in junior operators (p = 0.038). They were more frequent with silicone polishers than with tungsten carbide burs (p = 0.0005) and were reduced using dental loupes (p = 0.0090). Junior operators worked faster than senior operators (p = 0.031), but the latter were quicker when using the dental loupes (p = 0.012). Aligner CA removal induces enamel damage or leaves composite remnants on its surface. The presence of composite remnants is influenced by the type of tool and can be reduced by using dental loupes, which also lowers working time.

Orthodontic debonding and enamel surface integrity. A systematic review of the literature

The aim of a debonding protocol is to ensure the complete removal of composite resin without altering the enamel surface. A systematic review was conducted to analyze the effects of resin removal after the debonding of orthodontic brackets using different mechanical instruments, from both a qualitative and quantitative perspectives. An electronic search, following PRISMA guidelines, was conducted across three databases until March 2023, supplemented by a manual search. All controlled randomized studies or in vitro studies, comparing the removal of adhesive with tungsten carbide burs to other mechanical instrumentation techniques and assessing enamel surface, were included. Twenty-seven eligible articles were included, comprising two randomized studies and 25 in vitro studies, with varying bias levels. Compared to tungsten carbide burs, ultrasonic instruments and sandblasting showed similar or better results in terms of enamel loss and surface roughness. The enamel surface was equally less rough when using discs (Sof-Lex) or a fiberglass bur, or a fiberglass bur, although these techniques were time-consuming. The exclusive use of a diamond bur, stainless steel bur, or manual scaler for complete resin removal resulted in much rougher surfaces, clinically unacceptable. Preserving the enamel surface seems optimal with a two-phase protocol, involving the use of tungsten carbide burs for initial removal of most of the resin, followed by a less invasive technique for finishing resin removal. Beyond the findings of this review, a final polishing step also appears to be relevant.

A novel 'stop-hole' strategy to extend the fatigue life of orthodontic thermoformed retainers: an in vitro study.

This study aimed to investigate the potential to limit crack propagation in thermoformed retainers (TRs) and extend their fatigue life by placing a 'stop-hole'. Thirty-two TRs, fabricated from 1mm thick, round polyethylene terephthalate glycol (PETG) blanks of ICONIC®, underwent testing within a custom-built fatigue tester. After initial crack growth of 3mm, the TRs were divided into three groups: a control group (C) and two experimental groups based on the stop-hole placement method. In the first experimental group, stop-holes were placed using a 1mm round carbide bur on a slow-speed handpiece (ES), while the second group utilized a heated 1-mm-width ball-ended CPITN probe (EH). Following the placement of a stop-hole at the crack-tip, all 32 TRs resumed testing until the final crack length of 10mm was reached. Stop-hole placement significantly prolonged the delay in crack re-initiation in both experimental groups compared to the control group (P < .001 for both). The mean re-initiation times for the ES and EH groups were 104.50 and 129.50min, respectively, whereas the control group was 28.94min. Consequently, this discrepancy was reflected in the total testing times, with both experimental groups requiring significantly longer time to reach the final crack length (P < .001). There was no significant difference in the testing times between the two experimental groups. This is an in vitro study. The stop-hole methodology significantly extended the fatigue life of a TR in a controlled laboratory environment.

Effects of Finishing on Surface Roughness of Four Different Glass-Ionomer Cements and One Alkasite: In Vitro Investigation over Time Using Aging Simulation.

In 2017, Europe implemented a ban on amalgam restorations for children aged <15 years and for pregnant/breastfeeding women, highlighting the need for alternative filling materials exhibiting less surface roughness and enhanced longevity. This in vitro study aimed to examine the surface roughness variations of five amalgam-replacement materials across three time points and using six finishing methods: (1) no finishing (control), (2) Arkansas burs, (3) diamond burs, (4) tungsten carbide burs, (5) SofLex discs in descending grit size, and (6) coarse SofLex discs combined with silicone polishing. We prepared 960 samples. Each material group, i.e., Cention Forte (CNF), DeltaFil (DLF), Ketac Universal (KTU), IonoStar Molar (ISM), and Equia Forte HT (EQF), comprised 60 samples (n = 10 per finishing method) created using standardized 3D-printed metal molds. Surface roughness (Sa) was measured immediately after finishing, after 30 days of storage in distilled water, and after thermocycling (5000 cycles) using a non-contact profilometer. The results indicate that conventional and hybrid glass-ionomer cements have smoother surfaces than high-viscosity GICs. The DLF and CNF groups exhibited stable outcomes. These findings underscore the importance of selecting appropriate finishing methods based on the restorative material to minimize surface roughness.

Comparative evaluation of blood contamination on the push-out bond strength of mineral trioxide aggregate, Biodentine, and bone cement in furcation perforation repair: An in vitro study

ABSTRACT Aim: This in vitro study was designed to compare the effect of blood contamination on the push-out bond strength of mineral trioxide aggregate (MTA), Biodentine, and bone cement. Materials and Methods: Seventy-eight human mandibular molars with furcation were selected and decoronated at the cementoenamel junction. The samples were mounted 3 mm below the furcation area into the acrylic resin. A perforation in the center of the furcation was made using a round carbide bur size 3 with a diameter of 1.2 mm. Then, the perforation was enlarged up to a standardized diameter of 1.3 mm using a size 5 Gates-Glidden drill. The samples were randomly divided into three groups. Based on blood contamination status, each group (n = 26) was further subdivided into two subgroups (n = 13). Whole fresh human blood was obtained from the principal investigator of the research group. A 27-gauge syringe was used to inject blood into the perforated furcal area. A piece of gelatin was packed under the furcal area using a condenser. MTA, Biodentine, and bone cement were mixed according to the manufacturer’s recommendations and compacted into the perforation. A universal testing machine was used to evaluate the push-out bond strength. Statistical Analysis: The results were analyzed using one-way analysis of variance followed by Tukey’s post hoc test (P &lt; 0.05). Results: In the experimental groups with blood contamination, Group 2A exhibited statistically significant push-out bond strength values compared with Group 1A and Group 3A. In the groups without blood contamination, Group 2B showed statistically significant push-out bond strength values compared with Group 1B and Group 3B. Irrespective of the blood contamination status, Group 3 exhibited higher push-out bond strength values than Group 1, with no statistically significant difference between the groups. No significant difference was observed within the groups. Conclusion: Biodentine showed promising results as a better perforation repair material irrespective of the status of blood contamination. Bone cement can be a viable alternative material for furcation perforation repair compared with MTA.

Comparison of pain and efficacy of caries removal using tungsten carbide bur versus chemomechanical agent (Brix Gel): A randomized controlled trial.

Objective: To compare the pain response and efficacy of caries removal using tungsten carbide burs with that of using Brix Gel as a chemomechanical caries removal agent. Study Design: Randomized Controlled Trial. Setting: Department of Operative Dentistry, PIMS, Islamabad. Period: November 2023 to April 2024. Methods: Conducted on 40 participants were selected using a non-probability technique. Participants aged 12 to 65 years with open occlusal carious lesions involving dentin were included. Patients with symptoms of pulpitis, caries affecting maxillary or mandibular anterior teeth, severe systemic illnesses, allergies, sensitivities, or pregnancy/lactation were excluded. Caries removal methods were randomly assigned. Pain levels were assessed using a Visual Analog Scale (VAS), and caries removal efficacy was evaluated. Statistical analysis was done using chi-square and independent samples t test. Results: Among the 40 participants, 47.50% were female, and the mean age was 36.30±15.57 years. Mandibular molars were the most commonly affected teeth (n=24, 60%). No significant difference in age or gender distribution was observed between the two groups. The chemomechanical method resulted in significantly lower pain scores compared to carbide bur (2.59 ± 1.34 vs. 4.44 ± 1.61, p &lt; 0.001). Pain severity also differed significantly between groups, with more mild pain reported in the chemomechanical group (80.00% vs. 5.00%, p &lt; 0.001). However, caries removal efficacy did not significantly differ between the two methods (p = 0.48). Conclusion: Chemomechanical caries removal using Brix Gel demonstrated superior pain management compared to carbide bur. While both methods showed similar efficacy in caries removal, the chemomechanical approach may offer better patient comfort during the procedure.

Comparison of proximal contact and contours of class II restoration in premolars and molars restored with three different matrix systems using FDI criteria: An in vivo study.

Sectional matrix systems, namely, Garrison and Bioclear with contact rings, are valuable aids to establish proximal contact tightness and contours in Class II composite restorations when compared with the circumferential matrix system Tofflemire. This study aimed to compare the proximal contact and contours of Class II restoration in premolars and molars restored with Tofflemire, Garrison, and Bioclear matrix system by FDI criteria of approximal anatomical form using floss or 25-µm metal blade and radiographic examination. Sixty Class II patients were selected, and a preoperative bitewing radiograph was taken. Initially, caries removal was done by round diamond bur, followed by 245 carbide bur. Samples were divided randomly into three groups based on the type of matrix system used for restoration. Group 1 (n = 20): Tofflemire, Group 2 (n = 20): Garrison matrix system, and Group 3 (n = 20): Bioclear matrix system. Matrix systems were applied according to the manufacturer's instructions, and composite restoration was done. The clinical evaluation of proximal contact and contour was done by a blinded observer immediately after placement of composite restoration using FDI criteria by passing dental floss or 25-µm metal blade, whereas marginal gaps and overhangs were checked using a radiograph. Results were statistically analyzed. The statistical analysis was done using the Statistical Package for the Social Sciences (SPSS for Windows, Version 19.0). Descriptive statistics was calculated as frequency and percentage. The comparison of characteristics of the contact points, contour, and radiographic examination was carried out using the Chi-square test. Multiple comparisons were done by comparing column proportions with Bonferroni adjustments. The level of significance for the present study was fixed at P < 0.05. There were significantly higher proportions of normal contacts in Garrison (60%) and Bioclear (70%) compared to that in the Tofflemire (20%) matrix system (Bioclear > Garrison > Tofflemire). Comparison of contours showed normal contours with Garrison (50%), Bioclear (50%), and Tofflemire (15%) matrix system (Bioclear = Garrison > Tofflemire). In radiographic examination, harmonious transitions between the restoration and the tooth were similar in Garrison (30%) and Bioclear (30%) compared to the Tofflemire (15%) matrix system (Bioclear = Garrison > Tofflemire). Garrison and Bioclear sectional matrix systems established superior contacts and contours than the Tofflemire circumferential system.

Effect of adhesives and mechanical surface treatments on the hard relining of CAD-CAM denture bases.

The aim of this study was to evaluate the impact of mechanical roughening, adhesive applications, and aging on the bonding between CAD-CAM denture base materials with distinct chemical contents and hard relining material. A total of 300 denture base specimens were produced by additive, subtractive, and conventional heat-polymerization techniques (N=100). The specimens have been classified into five subgroups based on the particular surface treatments administered (n=20): (1) Hard relining material's adhesive application (control); (2) Tungsten carbide bur application for 1min, and hard reline material's adhesive application; (3) Airborne-particle abrasion (APA) with 110 μm Al2O3, and hard reline material's adhesive application; (4) Scotchbond Universal application; and (5) Visio.link application. Representative specimens from each subgroup were examined under a Scanning Electron Microscope (SEM). Subsequently, self-cure hard relining material was condensed in the center of the specimens. Half of the specimens were thermally aged with 5000 cycles at 5°C-55°C. The shear bond strength (SBS) test was performed, and failure loads were recorded. The data was evaluated by Robust ANOVA and Bonferroni test (p<0.05). No statistically significant difference was obtained between the production techniques (p = 0.051). The lowest SBS was observed in the control group among surface treatments, while mechanical surface treatments and universal adhesive showed the highest SBS for both aged and non-aged groups. Aging caused a significant decrease for all test groups (p=0.001). Mechanical surface treatments and universal adhesive applications are more effective for maintaining adhesion across all production techniques.

The use of modified nickel–titanium rotary file for preparing staging platform to retrieve instrument fragments from narrow and curved canal

Abstract Staging platform (SP) uses a modified Gates Glidden (GG) to help retrieve separated instruments deep in the root canal. However, GG drills may cause damage or severe dentin loss. A 46-year-old male patient was referred to the endodontic postgraduate clinics complaining of pain on biting related to the mandibular right second molar (#47). The preoperative periapical radiograph of #47 showed a previously initiated root canal treatment with an approximately 8-mm separated instrument in the apical third of a curved mesiolingual canal. A nickel–titanium (NiTi) rotary file size 25/0.04 was flattened with a carbide bur. The modified file was then used to create a centered SP. After SP was achieved, an ultrasonic tip was used at lower power for the trephination of dentin. The fragment became loose, and retrieval was achieved. The use of a modified NiTi rotary file presented a safe and alternative option to establish SP for instrument retrieval instead of using GG drills.

Evaluating the effectiveness of color changing adhesives versus ultraviolet absorbent dye additive adhesives in the removal of adhesive remnants after orthodontic debonding

The fixed orthodontic treatment initiates with bonding and ends up with debonding of brackets which alters the enamel surface. The adhesive remnants present on the enamel surface after debonding are removed with the help of various aids but alters the enamel surface to an extent and there is no alternative material or instrument for removing the adhesives. The aim of the study was to compare the effectiveness of color changing orthodontic bonding adhesives versus ultraviolet absorbent dye additive orthodontic bonding adhesives in the removal of adhesive remnants after orthodontic debonding.: 40 extracted human premolars were procured and metal brackets were bonded to the buccal surface with Group 1 – Enlight, Group 2 – Grengloo, Group 3 - Brace Paste &amp; Group 4 – Enlight + UV dye additive. Debonding of brackets were done in INSTRON and evaluated for ARI score in stereo microscope and photo micrographs were taken to analyze the surface area in ImageJ software with conventional and UV light source. Then the adhesive remnants were removed with tungsten carbide bur at low speed with appropriate illumination and the enamel surface is assessed under scanning electron microscope for EDI score. This study resulted with time taken for the removal of adhesive remnants between the 4 groups and indicates statistically significant difference (p&amp;#60;0.05). Group 3 (Brace Paste) possesses the less time taken for the removal of adhesive remnants between the other three groups and shear bond strength reveals a statistically significant difference (p&amp;#60;0.05) between the three adhesive groups. This current study concluded that the color changing adhesives with the fluorescence property were significantly different when compared with other adhesives due to the reduction in time taken for the removal of adhesive remnants from the enamel surface with minimal damage. Additionally the introduction of a UV dye additive for the visual distinction between the enamel structure and adhesive remnant also proves to be a valuable aid in the assessment of adhesive remnant index and removal.

The effect of surface treatment and thermal aging on the bonding of clear aligner attachments to provisional resin-based material: shear bond strength analysis.

The aim of this study is to evaluate the effect of different surface treatments on the shear bond strength (SBS) of clear aligner attachments bonded to Bis-acryl provisional crowns. 120 cylindrical bisacrylic composite material (ProTemp type) specimens were prepared and divided into six groups (n = 20) based on surface treatment, control: (no treatment); super coarse grit diamond bur, carbide bur, alumina-blasting, non-thermal plasma treatment, and Er:YAG laser treatment. The features of treated surfaces were examined using scanning electron microscopy (SEM). A flowable composite resin (Transbond XT; 3M Unitek) was bonded to the specimens forming the attachment. Half of specimens were subjected to thermal cycling (5,000 cycles). SBS was measured before and after thermal cycling. Each specimen was loaded at the attachment/resin interface at a speed of 0.5 mm/min until failure. The nature of the failure was analyzed using the composite remnants index (CRI). Two-way ANOVA and Tukey HSD were used for data analysis α = 0.5. For CRI scores analysis, Kruskal-Wallis test and Dunn's multiple comparison were used as post-hoc test. SEM analysis showed that all surface treatments altered surface properties and increase surface bonding area. The specimens treated with plasma, Er:YAG laser, and alumina-blasting had higher SBS values before and after thermal cycling. In comparison to control plasma, Er:YAG laser, and alumina-blasting showed a significant increase in SBS (P < 0.001) while carbide and diamond bur groups showed no significant differences (P > 0.05). Thermal cycling significantly decreased the SBS of control, carbide bur, diamond bur, and Er:YAG laser while no significant effect of alumina-blasting and plasma group. Er:YAG laser and plasma groups significantly exhibited more dominance for scores 2 and score 3 and the absence of score 0. Alumina-blasting, Er:YAG laser, or non-thermal plasma surface treatments increased the shear bond strength between clear aligner attachments and resin-based restorations.

Effectiveness of Sectioning Method and Filling Materials on Roughness and Cell Attachments in Root Resection Procedure.

The purpose of the present study was to investigate the created roughness and cell attachment of intact teeth (C), obturated teeth with bioceramic (BR), or epoxy resin (AH) after root resection using piezoelectric ultrasonic and carbide bur. Three groups of first mandibular premolars were used in the present study: control group (without any preparation or obturation) (C); second group was obturated with an epoxy resin sealer (AH, AH Plus Jet); and finally, the third one was obturated with a bioceramic sealer (BR, BioRoot RCS). All teeth were incubated for 4 months at 37°C. After that, the samples were sectioned using tungsten carbide bur or piezoelectric ultrasonic. Roughness and then cell attachment of periodontal ligament cells on the sectioned surfaces were investigated by profilometer and confocal microscope, respectively. Data were statistically analyzed using one-way analysis of variance. After root resection, no significant difference was found between the roughness among the three groups sectioned using the piezoelectric technique (p > 0.05). In contrast, concerning the sectioned samples by burs, C demonstrated a rougher surface compared with BR (p < 0.05). There was a significant higher cell attachment in BR compared with AH in the piezoelectric groups (p = 0.047), while no statistically significant difference was found between the groups sectioned with bur (p > 0.05). Dentists are now focused on the use of calcium silicate-based sealers due to their bioactivity. The present study advises dentists to use bioceramic sealer which could improve the dentin characteristics which ameliorate the cell attachment.

Comparative Evaluation of Clinical and Microbiological Assessment of Caries Excavation Using Conventional, Smart Bur, Chemomechanical Method and ErCr:YSGG Laser

ABSTRACT Objectives: Caries removal efficacy in terms of microbiological burden using Tungsten Carbide Bur No. 330, Polymer bur, BRIX 3000, and ErCr:YSGG Laser. Methods: Class I open dentinal caries was selected and divided into four groups (n = 15) depending on caries excavation methods. Group I: Tungsten carbide (TC) No 330-bur; Group II: Polymer bur (Smart bur); Group III: Brix 3000 gel; Group IV: Erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er:Cr:YSGG) laser. Two samples of carious material, before and after caries excavation, were taken and cultured on blood agar plates. Multiple comparison of mean CFUs/ml between different groups was done using Dunn’s post hoc test and Wilcoxon signed-rank test. Results: Group I showed significantly lesser mean CFUs/ml followed by Group IV as compared to Group II and Group III. Conclusion: Within the parameters and limitations of the present study, ErCr:YSGG laser can be a helpful aid as a minimally invasive method of caries excavation.

Salivary levels of eluents during Invisalign™ treatment with attachments: an in vivo investigation

BackgroundThe aim of the present study was to investigate qualitatively and quantitatively the elution of substances from polyester-urethane (Invisalign™) aligners and resin composite attachments (Tetric EvoFlow) in vivo.MethodsPatients (n = 11) treated with the aligners and attachments (16 per patient, without other composite restorations) for an average of 20 months, who were planned for attachment removed were enrolled in the study. Patients were instructed to rinse with 50 mL of distilled water upon entry and the rinsing solution was collected (before removal). Then, the attachments were removed with low-speed tungsten carbide burs for adhesive residue removal, a thorough water rinsing was performed immediately after the grinding process to discard grinding particle residues, and subsequently, after a second water-rinsing the solution was collected for analysis (after removal). The rinsing solutions were analyzed for targeted (LC-MS/MS: Bis-GMA, DCDMA, UDMA, BPA) and untargeted (LC-HRMS: screening of leached species and their degradation products) compounds.ResultsTargeted analysis revealed a significant reduction in BPA after attachment removal (4 times lower). Bis-GMA, DCDMA, UDMA were below the detection limit before removal but were all detectable after removal with Bis-GMA and UDMA at quantifiable levels. Untargeted analysis reviled the presence of mono-methacrylate transformation products of Bis-GMA (Bis-GMA-M1) and UDMA (UDMA-M1), UDMA without methacrylate moieties (UDMA-M2), and 4-(dimethylamino) benzoic acid (DMAB), the degradation product of the photo-initiator ethyl-4-(dimethylamino) benzoate (EDMAB), all after attachment removal. Several amino acids and endogenous metabolites were also found both before and after removal.ConclusionsElevated levels of BPA were traced instantaneously in patients treated with Invisalign™ and flowable resin composite attachments for the testing period. BPA was reduced after attachment removal, but residual monomers and resin degradation products were found after removal. Alternative resin formulations and attachment materials may be utilized to reduce eluents.

Effect of milling procedures in CAD-CAM systems on the color changes of CAD-CAM polymethyl methacrylate resin material as interim material

PurposeThis study aimed to investigate the effects of new and used burs on CAD-CAM PMMA resin color changes following thermocycling.Materials and methodsTwenty disk-shaped specimens (10 × 2 mm) were made using a single brand of CAD-CAM polymethyl methacrylate resin (Polident) for the color test. Group N consisted of half of the specimens that were machined using the new tungsten carbide bur set, and Group U consisted of the specimens that were milled using the used bur set (500 machining time). A color test was performed on the specimens both before and after thermocycling. For the statistical analysis, the Kruskal-Wallis and Dunn Pairwise Comparison tests were employed.ResultsThe ∆E* value of specimens (2.057) milled with the used bur was higher than those of specimens milled with the new bur (0.340), but this value is within clinically acceptable limits. After thermocycling, specimens milled with the utilized burs had the greatest L* (93.850) and b* (5.000) values. After thermocycling, statistically significant differences were discovered between Group N and Group U as well as between specimens milled with the utilized bur before and after thermocycling.ConclusionThermocycling process have an effect on the mean ∆E values of specimens milled with the used carbide bur, but these ∆E* values were not statistically significant.Clinical significanceThe color and clinical performance of CAD-CAM restorations may be affected by variations in CAD-CAM milling bur properties, particularly those related to their frequent use.

Enamel surface roughness following debonding resin clean up using high speed air-turbine and electric handpieces. In vitro study

BackgroundHigh speed electric handpieces have recently been growing in popularity among dental professionals. Advantages include smoother surface preparation and increased cutting efficiency.AimThe primary objective was to compare enamel surface roughness following resin cleanup after bracket debonding using highspeed air turbine versus electric handpiece. The secondary objective was to record the time needed for resin-clean up.MethodForty deidentified freshly extracted human premolars were cleaned and sectioned at the cement-enamel junction. The crowns were embedded in acrylic blocks. Enamel surface roughness parameters (Ra, Rz, Rp and Rv) were measured using a stylus profilometer. Brackets were bonded using a light-cure orthodontic adhesive and stored in distilled water for 24 h. Following bracket debonding, the specimens were randomly divided into 2 groups: First group: resin clean-up was carried out using a 12-fluted carbide bur mounted on a high-speed air turbine; and second group: where an electric handpiece was used. Surface roughness parameters were measured following resin clean up and after polishing using pumice and a rubber cup. Time needed for resin clean-up was recorded. Differences in enamel surface roughness and time between groups were compared using repeated measures ANOVA and independent samples t-test, respectively at P ≤ 0.05.ResultsThe electric handpiece groups showed significantly higher values for Ra, Rz and Rp both following resin cleanup and polishing. Time taken for resin cleanup was significantly longer for the electric handpiece group.ConclusionConsidering both surface roughness and time, electric handpiece do not seem to add greater effectiveness or efficiency to resin cleanup following orthodontic bracket debonding.

Assessing the Impact of Various Decontamination Instruments on Titanium and Zirconia Dental Implants: An In Vitro Study.

This study investigates the impact of various instrumentation techniques on material removal and surface changes in titanium (Ti)- and zirconia (Zr) implant discs. Ti- and Zr discs were subjected to standardized experiments using various instruments including airflow, ultrasound, carbide, and diamond burs. Instrumentation was performed for 60 s with continuous automatic motion. Abrasion and changes in surface roughness were assessed using profilometry, while scanning electron microscopy was used to examine morphological changes and particle size. Carbide burs predominantly caused abrasion on Ti discs, while diamond burs caused more abrasion on Zr discs. The Ti discs were more susceptible to surface changes. However, among the materials tested, machined Zr discs treated with diamond burs produced the largest particle. In certain cases, a statistical significance (p < 0.05) was observed between the groups, while in others, there was no considerable difference among the means (p > 0.05). These results highlighted the statistical significance of our findings. These results found diverse alterations in surface characteristics of Ti- and Zr discs due to different instruments, with carbide and diamond burs causing notable effects. The findings highlight the need for a careful balance between promoting healing and minimizing harm during implantoplasty.

Adaptability of VisCalor versus bulk-fill composites using scanning electron microscope: an in-vitro study

Purpose To evaluate the marginal integrity of two types of bulk-fill composite resins in Class I box-shaped cavities. Materials and methods Forty extracted human sound molars were selected. The teeth were fixed with sticky wax to the base of plastic cylinder and the cylinder was filled with self-curing acrylic resin so that only root was embedded. Simple Class I box-shaped cavities were prepared using a fissure carbide bur with water spray and finished with fine-grained flame burs. The overall dimensions and depth of the cavities were standardized as follows: 4 mm length mesiodistally and 3 mm width buccolingually and up to 4 mm depth. All prepared cavities were bonded using Futurabond M+ one-step self-etch adhesive system. The teeth were randomly divided into two groups (n = 20 teeth each): group I: specimens were restored with VisCalor composite bulk-fill composite resin, which is heated before insertion using a VisCalor dispenser dental device. Group II: specimens were directly restored with X-tra fill bulk-fill composite resin without preheating. After curing, finishing and polishing were performed. Each group was subdivided into two subgroups a and b (n = 10) according to whether subjecting 500 thermocycling fluctuations or not. Each specimen was sectioned buccolingually through the center of the composite resin restoration in two halves, and then cleaned under running tap water and subjected to thorough ultrasonic cleaning to get rid of both soft and hard surface deposits. All sectional samples were fixated in cylindrical carriers, and a thin layer of gold was applied to the surfaces. The marginal adaptation of composite restorations and ultramorphology of adhesive bonds were analyzed at ×50, ×1000 magnification, with a scanning electron microscope. ×50 magnification was utilized to measure the length of margins free gap in enamel and dentin by Autodesk Auto CAD program and expressed in mm/percent. All data of measurements of the length of nongaped margins in enamel and dentin are collected, tabulated, and statistically analyzed. Results Group Ia (VisCalor bulk-fill not thermocycled), recorded the highest mean value of marginal free-gap with 10.26 ± 0.27 mm (93.31%), while group IIb (X-tra-fill bulk-fill thermocycled) recorded the lowest mean value in 7.90 ± 0.26 mm (73.04%) and the difference was statistically highly significant (P = 0.000). In general, group I recorded higher mean values of marginal free gap and adaptation in mm/percent than group II, and the difference was statistically highly significant at P value of 0.000 (9.86 ± 0.55 and 8.23 ± 0.39 mm and 89.15 ± 5.38 and 74.89 ± 3.69%, respectively). Bulk-fill restorations without thermocycling exhibited a higher mean value of marginal free gap and adaptation in mm/percent than the thermocycled one with a significant difference recorded at P value of 0.005. Conclusion Using preheated VisCalor bulk-fill composites could decrease the marginal gap formation improving the continuity at the tooth–restorative material interface than conventional bulk-fill restorations. On the other hand, thermocycling.

Topography of root-end surface after freehand and three-dimensional-guided apicoectomy procedure: A scanning electron microscope study.

Dentinal microcracks formed during apical resection may lead to increased susceptibility to root fracture and improper sealing of apical preparation that may negatively influence the outcome of endodontic microsurgery. This study was performed to analyze the root-end surface for dentinal microcracks using a scanning electron microscope (SEM) after resection with high-speed bur and trephine drill. Thirty extracted single-rooted maxillary premolar teeth were selected and randomly distributed into two groups (n = 15). Working length was established using a #15 K-type file. Canals were prepared with a rotary Ni-Ti system to size 30/0.06 using endomotor, irrigated with 3% sodium hypochlorite, dried with paper points, and obturated with gutta-percha cones using a single-cone technique. All samples were mounted on preformed molds and poured using a mixture of sawdust and gypsum. In Group A; tungsten carbide bur was used to perform a freehand apicoectomy. In Group B; a trephine drill was used with a three-dimensional guide to perform 3 mm of root resection. Apicoectomy was performed in both groups under a dental operating microscope. Resected root ends were inspected for microcracks using SEM. The Shapiro-Wilk and Mann-Whitney U-test were used for statistical analysis. Microcracks were observed in all samples in both study groups. Trephine drill produced more microcracks on the resected root surface compared to the use of high-speed tungsten carbide bur with a statistically significant difference (P < 0.05). The trephine drill used during targeted endodontic microsurgery produced more microcracks on the resected root dentine surface compared to the high-speed tungsten carbide bur used during freehand apicoectomy.

Complete versus incomplete caries removal procedures and their effects on dental pulp in primary teeth - An in vivo study.

Dental caries results from an ecologic shift within the dental biofilm from a balanced population of microorganisms to an acidogenic, aciduric, and cariogenic microbiological population developed and maintained by frequent consumption of fermentable dietary carbohydrates. Total caries removal (TCR) of deep lesion may result in pulpal exposure requiring more invasive treatment. Hence, current pediatric dentistry has shifted to minimally invasive treatment that avoids more complex, time-consuming procedure, and the child's discomfort. The aim of this study is to evaluate and compare clinical performance and radiographic changes after complete and incomplete caries removal procedures. The study was conducted on 60 primary molars in children aged 6-9 years. Selected 60 primary molars were randomly divided into two groups. Group 1 (PCR): infected dentin was removed, while the affected dentin was maintained on the pulpal wall. Group 2 (TCR): both infected and affected dentin were removed through low-speed carbide bur and hand excavator. Teeth were evaluated at 4 and 6 months clinically and radiographically. The proportion was compared using Fisher's exact test. The Statistical Package for the Social Sciences version 21 was used for analysis. The level of significance was kept at 5%. The clinical and radiographic success rates of ICR and CCR in primary teeth with deep carious lesions were high and did not differ significantly, indicating that the retention of carious dentin does not interfere with pulp vitality. Thus, ICR is a reliable minimally invasive approach that might replace the CCR in primary teeth when correctly indicated.