Round Diamond Research Articles

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.

Exploring access cavity through non-carious cervical lesions: Impacts on instrumentation, obturation, and fracture resistance in mandibular incisors.

To compare the effects of Cervical Access Cavity (CervAC) and Traditional Access Cavity (TradAC) on root canal preparation, root canal filling, and fracture resistance in mandibular incisors. Twenty recently extracted and intact mandibular incisors were initially scanned using a micro-CT device. The specimens were anatomically matched to create two groups (n = 10). A wedge-shaped non-carious cervical lesion (NCCL) was created on the buccal aspect of all teeth using a double-faced segmented diamond disc. In group 1, a TradAC was prepared, whilst in group 2, access was created through the simulated NCCL using a round diamond bur 1012. After root canal preparation with Rotate instruments sizes 15/0.04, 20/0.04, and 25/0.04, the teeth were scanned again and evaluated for root canal volume and surface area, static voxels, volume of removed dental tissue, and dentine thickness. After that, the root canals were filled using the single-cone technique, teeth were restored with composite resin, and subsequently rescanned to calculate the volume of filling materials and voids. Then, the restored teeth were subjected to fracture resistance tests using a universal testing machine. Statistical comparisons between groups were performed with the Mann-Whitney test or the Student's t-test, with a statistical significance level of 5%. Statistical comparisons indicated no significant differences between groups in terms of root canal volume, surface area, static voxels, removed root dentine, root canal filling volume, percentage of voids, or fracture resistance load (p > .05). Conversely, teeth prepared with TradAC showed a significantly higher percentage of dental tissue removed from the crown (p = .001) and a greater volume of filling material remnants in the pulp chamber (p < .001) compared to the CervAC group. A significantly lower percentage reduction in dentine thickness was observed only on the mesial aspect of root at Level 1 in TradAC group (p = .008). CervAC can be considered a viable alternative approach in the presence of NCCL in mandibular incisors.

Effect of Apical Preparation on Different Needle Depth Penetration.

Introduction: Irrigation is a fundamental part of endodontic debridement as because it allows for cleaning beyond what might be accomplished by root canal instrumentation. The flushing action produced by the irrigant and the penetration of the irrigant is not dependent only on the anatomy of the root canal system, but also on the depth of placement, system of delivery, the volume and fluid properties of the irrigant. Aim: The aim of the study was to evaluate the effect of apical preparation on the penetration depth of different types of needles. Methods: Thirty single-rooted lower premolar teeth were involved in this study. The access opening was performed by using a round diamond bur turbine (diameter 12) and Kfiles (diameter 15) were used for initial penetration in the canal. Stereo- microscope under 20 magnifications was used to determine the working length of the canal. Then the canals were prepared using protaper next in continuos rotation according to manufacture instructions with sequence files reached the WL (X1, X2, X3, X4). 4 mL of 5.25% NaOCI was used between each instrument. Three different types of endodontic needles were used. Needles size 27, 30-gauge stainless steel and IRRIFLEX endodontic irrigation needle. Each needle was inserted in the canal and its length of penetration was measured before canal preparation and after finishing files then the depth of penetration was measured. Results: ANOVA test showed that there are significant differences among all groups also results show a significant difference when comparing 27 with 30 needle gauge irriflex but there was no significant difference between the needle gauge 30 and irriflex. Conclusion: This study shows that the penetration depth of needles influences on apical preparation it appears that 27 -gauge needles show less depth penetration when compared to irriflex and 30- gauge needles. Keywords: apical, needle, penetration depth, endodontics.

Anisotropic material removal in ultra-precision grinding of rounded diamond cutting tools

Rounded diamond cutting tools are extensively utilized in ultra-precision cutting applications. However, the anisotropic nature of diamond crystals poses challenges in achieving uniform and controllable material removal using conventional mechanical grinding techniques, impeding further improvements in the precision of diamond tools. This study introduces a novel approach that leverages the diamond dynamic micro tensile strength theory to establish a grinding factor prediction model for any position on the flank face of the tool, considering the combination of R(100)F(100) and R(110)F(100) crystal faces. Experimental investigations are conducted to examine the relationship between the model and the tool's material removal rate. The findings reveal pronounced anisotropy on the flank of the diamond tool during mechanical grinding, and the modified grinding factor model exhibits excellent agreement with the observed change in the material removal rate. These outcomes provide valuable insights for enhancing precision in diamond tool fabrication and advancing ultra-precision cutting techniques.

The Effect of Different Sealer Removal Protocols on Micro-Tensile Bond Strength of Single Bond Plus to Dentin Exposed with Different Chemical Root Canal Irrigants: An Ex Vivo Study

Background: Chemical substances used to prepare root canals and their residuals can alter dentin surface composition, affecting restorative systems bonding to dentin. Objectives: This ex vivo study evaluated the effects of different sealer removal methods on the micro-tensile bond strength of dentin surfaces exposed using endodontic irrigants. Methods: A total of 45 extracted healthy mandibular molars were sliced from the occlusal surface to expose their dentin surface and were randomly divided into three main groups (n = 15) based on the irrigants as G1: Distilled water (control), G2: Sodium hypochlorite (NaOCL) 5.25%, and G3: Chlorhexidine (CHX) 2%. AH Plus endodontic sealer, was applied to all exposed dentin surfaces. Each group was divided into four subgroups (SG) according to the sealer removal methods: SG1: No root canal sealer (control), SG2: Moist cotton pellet, SG3: Ethanol 95% saturated cotton pellet, SG4: Round diamond bur. The teeth were restored using single bond plus and Z250 composite and sectioned to prepare sticks for micro-tensile bond testing. Additionally, failure patterns were investigated. Comparison between experimental groups was performed using Kruskal-Wallis H and Dunn's post-hoc tests. The accepted significance level for all tests was P &lt; 0.05. Results: A significant decrease was observed in the micro-tensile bond strength of the control group cleaned with 95% Ethanol saturated cotton pellets. In addition, the highest micro-tensile bond strength was observed in dentin cleaned through a diamond round bur and in the group irrigated with CHX. The failure modes were mainly adhesive. Conclusions: Within this study's limitations, the dentin bond strength is affected by the irrigation protocol and sealer removal method.

Incorrect management of a broken abutment screw

&#x0D; Implant abutment screw fracture is an uncommon though challenging complication. A fractured abutment screw should be removed without damaging the threads of the screw channel to reuse the prosthesis.&#x0D; &#x0D; &#x0D; To retrieve the fractured part without severing the threads, various procedures have been proposed, such as to try to unscrew the fractured part using a strong, straight and pointed probe, or to prepare a small dent into the center of the fractured part using a small round diamond burr or a fissure burr in a counter clockwise motion. Various screw removal kits have been introduced to this aim, but with inconsistent results. &#x0D; &#x0D; &#x0D; When a physician does not manage to remove the fractured screw in either way, he/she often chooses to either replace the implant, which can be an expensive option, or abandon the implant and cover it with soft tissue, which may lead to compromised function, phonetics, or esthetics. Instead, saving the implant would great benefit patients. To this aim, the conversion of the screw chamber into a dowel space for a dowel-core and crown restoration has been proposed, thanks to the aid of laser-welded titanium for example. Instead, other techniques do not seem to have been commonly accepted. &#x0D; &#x0D; &#x0D; The aim of the present article is to present the incorrect management of a fractured abutment screw by a classic surtex post. &#x0D;

Comparison of Cleaning Efficacy of Different Rotary Files in Primary Teeth-An In vitro Study.

The aim of the present study was to comparatively assess the cleansing efficiency of dissimilar rotary files in deciduous teeth. Forty-five deciduous anterior teeth that had been subjected to extraction were chosen for this research. The teeth were included if they had a minimum of 2/3rd undamaged root portions. Coronal entrée was completed using round diamond burs. All 45 samples were allocated at random to one of the following three groups: Group I: Control group in which the radicular canal was not subjected to any form of instrumentation, Group II: The radicular canal was subjected to instrumentation employing rotary ProTaper files, Group III: The radicular canal was subjected to instrumentation with rotary MTwo files. The samples were subjected to immersion in a succession of diluted ethyl alcohols to permit dehydration: With a change of solution every eight hours, the first 16 hours were spent in 70% alcohol, followed by eight hours in 80% alcohol, eight hours in 95% alcohol, and eight hours in 100% alcohol. The samples thus subjected to dehydration were cleared by immersion in methyl salicylate for six hours. Under a stereomicroscope with a 10x magnification, the root canals were examined by a person who was blinded to the groups in order to look for any traces of ink in the coronal, middle, and apical third of the canals. In the control group, greater residual remains were present in the apical 3rd at 2.16 ± 0.08 followed by the coronal 3rd at 2.02 ± 0.14, and then in the middle 3rd at 1.88 ± 0.10. While using the ProTaper files, greater residual remains were present in the middle portion at 1.68 ± 0.16, followed by the coronal third at 0.94 ± 0.09, then the apical third at 0.98 ± 0.22. Greater residual remains were again noted with the MTwo files in the mid-portion at 1.44 ± 0.18, followed by the coronal part at 0.86 ± 0.10 and then the apical part at 0.82 ± 0.04. Differences among these groups were statistically significant with a P value < 0.001. The present study concluded that either of the file types used exhibited reasonably lower remnant score values in the apical third versus the middle/coronal thirds. Nonetheless, MTwo type files delineated superior capacity at removing debris versus the ProTaper file types at the apical level.

Evaluation and comparison of transportation and centering ability of various pathfiles in the second mesiobuccal canal of maxillary first molars

Introduction: In root canal treatment, the glide path process is considered a primary action to increase the safet y and efficiency of nickel–titanium rotary files and prevent preparation errors. The present study aimed to evaluate and compare different glide paths in terms of transportation and centering ability of the curved, narrow second mesiobuccal (MB2) canal of maxillary first molars using cone-beam computed tomography (CBCT). Materials and Methods: First, periapical radiographs and CBCT were obtained from extracted maxillary first molars, and 125 teeth, whose mesiobuccal root curve was in the medium range (a curve angle of 20°–40°) and had separate MB2 canal, were selected. However, teeth &lt;17 mm and more than 21 mm in length were excluded from the study. Afterward, the access cavity was prepared with a round diamond bur, and the MB2 canal was negotiated using a manual size 6–8 C-pilot. In the next stage, were randomly divided to five groups of 25, and each group was prepared by using one of the files of ProGlider, R-Pilot, Hyflex EDM, WaveOne Gold Glider, and C-Pilot. Following that, CBCT was taken from all teeth again, and the levels of canal transportation and centering ability were evaluated at five levels (distances of furcation, 1 and 2 mm from the furcation, the crest of the curvature, and 1 mm from the apex). Results: In this study, there was no statistically significant difference in canal transportation and centering ability among five PathFile systems in all sections (P &gt; 0.05). Conclusions: All five PathFile systems carry out Glide path preparation similarly and appropriately in terms of canal transportation and centering ability.

Key Technologies and Applications for Lapping Micro Round Diamond Tools

Key Technologies and Applications for Lapping Micro Round Diamond Tools

Accidental Ingestion of a Dental Bur during Endodontic Procedure: A Case Report

Accidental ingestion of dental materials and instruments during the routine dental procedures especially in young children can occur at any time. The aim of this case report was to highlight on the recognition and management of such condition immediately for the prevention of any adverse complications. A 3-year-old male child accidentally swallowed a round diamond bur that popped out of the air-rotor handpiece during access cavity preparation on 65. There were no signs of airway obstruction and immediate postero-anterior view of chest and abdomen showed the presence of bur in the gastrointestinal tract which got eliminated in stool on the fourth day, uneventfully.

Improving Safety in Chondrolaryngoplasty.

Improving Safety in Chondrolaryngoplasty.

Histologic and Histomorphometric Evaluation of a Connective Tissue Graft Retrieved with a Novel Deepithelialization Procedure: A Case Series.

Various free connective tissue graft (CTG) harvesting techniques have been reported. The lining epithelium of the palatal graft may be retrieved either intra- or extraorally. This report presents a series of root coverage cases where deepithelialization was intraorally performed before harvesting the graft with a round diamond bur mounted on a low-speed handpiece. Ten single-tooth gingival recession defects in five patients were treated, applying a surgical procedure based on a coronally advanced flap combined with a free CTG that was deepithelialized in situ by the same method. Recession and probing depths and keratinized tissue and recession widths were recorded at baseline and the follow-up evaluations. Follow-up was between 7 and 21 months (mean: 12.1 ± 5.04 months). Clinical, esthetic, and histologic evaluations were performed. Mean root coverage was 89% ± 24.86% (range: 25% to 100%), and complete root coverage was observed in 80% of cases; the esthetic score range was 6 to 9 (mean: 7.44 ± 1.01). Epithelial remnants, although different in proportions, were evident in all samples (range of prevalence: 4.57% to 29.12%). Within the limitations of the small number of clinical cases, the presented in situ deepithelialization technique for CTG seems to be valuable and may accordingly be routinely applied.

Histologic evaluation of dentin bridge formation by pachymic acid and biodentine in human tooth culture model

Histologic evaluation of dentin bridge formation by pachymic acid and biodentine in human tooth culture model

SEM Evaluation of Various Intracanal Irrigation Devices on Smear Layer Removal: A Comparative Study

The present study aimed at assessing the effectiveness of different intracanal irrigation devices on the removal of the smear layer. The recently extracted 80 lower premolars having single canal were chosen for this in vitro study. A round diamond bur was used to gain endodontic access and the root canal was entered with a #15 K-file until the tip was just seen at the apical foramen. Manual instrumentation of root canals of all teeth was done using the step-back method. The samples were later divided randomly into four groups. Later, each sample was exposed to final irrigation by using four different irrigation systems, group 1: conventional needle irrigation, group 2: irrigation with ultrasonic activation, group 3: irrigation with EndoVac system activation, group 4: irrigation with EndoActivator. The samples were next mounted and visualized under scanning electron microscope (SEM) for the absence or presence of the smear layer. Irrigation with EndoVac system activation showed the presence of least smear layer (2.40 ± 0.32), followed next by EndoActivator (3.24 ± 0.46) and ultrasonic activation (4.96 ± 0.54) and conventional needle irrigation (5.20 ± 0.10). No statistically significant difference was found in the apical and coronal thirds of the root canal in removal of the smear layer on an intragroup comparison. However, a statistically significant (p < 0.001) difference was seen between the groups at the apical and coronal thirds on an intergroup comparison. This study demonstrated the EndoVac system group to be efficient in removal of the smear layer when compared to the EndoActivator system, ultrasonic activation, and conventional needle irrigation group. The definitive objective of endodontic therapy is to transform the affected teeth to a healthy and functional state. The irrigants can reach the working length when delivered by an effective irrigation delivery system. This type of delivery system should deliver adequate volume of irrigants all the way up to the working length and have sufficient flow and be efficient at debridement of complete canal system.

Investigation of the Presence of SARS-CoV-2 in Aerosol After Dental Treatment

AimsThe objective of the present study was to investigate the presence of SARS-CoV-2 in aerosol and COVID-19 contamination distance asssociated with ultrasonic scaling and tooth preparation.MethodsTwenty-four patients with COVID-19 were included in this study. Removal of supragingival plaque with ultrasonic instruments for 10 minutes and high-speed air-turbine using for the simulation of cutting the maxillary right canine tooth with a round diamond bur for 5 minutes were performed. Patients were randomly assigned to 2 groups: In group A, medium-volume suction was used during treatment. In group B, high-volume suction with an aerosol cannula was added to medium-volume suction. Prior to treatment, 5 glass petri dishes containing viral transport medium were placed in the operating room. After treatment, petri dishes were immediately delivered to a microbiology laboratory for real-time polymerase chain reaction (RT-PCR) analysis.ResultsRT-PCR test results were negative for all specimens in group B. However, 5 positive test results for COVID-19 were detected in group A specimens.ConclusionsSuction with an aerosol cannula is very important to prevent COVID-19 viral contamination via aerosol. In addition, a high-volume suction capacity (air volume) of 150 mm Hg or 325 L/min is sufficient for elimination of viral contamination. Thus, high-volume suction should be used during dental treatments in COVID-19 patients.

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.

Efficiency of calcium hydroxide removal techniques from simulated internal resorptions - in vitro study

Introduction/Objective. Calcium hydroxide (CH) is the medicament of choice in endodontic treatment of internal root resorptions. The aim of the study was to compare the effectiveness of three different techniques for CH removal from simulated internal root resorptions. Methods. Twenty-nine extracted single-root teeth were prepared using NiTi rotary files of BioRaCe system (40/.04) following irrigation. A round diamond drill was used in the making of a symmetrical standardized internal resorptions 6 mm from the apex. Three techniques for CH removal from internal resorptions were tested: modified conventional syringe irrigation (CSI), passive ultrasonic irrigation (PUI), XP-endo Finisher (XP). Resorptive cavities and apical thirds were observed under a stereomicroscope (?45) and scored (from 1 to 5), while representative samples were analysed by a scanning electron microscope. Obtained results were statistically processed by Kruskal?Wallis and Mann?Whitney U-test (p &lt; 0.05). Results. The most efficient system was PUI, with 66.7% of samples rated 1 and 33.3% rated 2. The next one was XP, and the least efficient was CSI, with 33.3% of samples rated 1 (resorptive defect without medicament). There was a statistically significant difference between the PUI and CSI systems (p &lt; 0.05), while there was no difference between the PUI and XP systems. Conclusion. No system completely removed the CH from the simulated internal root resorption cavities. PUI was the most effective system for removing CH. The combination of techniques provides better performance in removing CH paste residues from the canal walls

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.

Influence of occlusal loading on peri-implant inflammatory cytokines in crevicular fluid: a prospective longitudinal study

ObjectiveThe objective of the study was to evaluate the relation between occlusal loading and peri-implant crevicular fluid cytokine expression in patients with implant-supported complete fixed prostheses in both arches.Material and methodsA prospective longitudinal clinical study was performed at a university clinic. Fifteen patients were selected and 11 were included. All patients had bimaxillary implant-supported complete fixed ceramo-metallic prostheses loaded at least 12 months before the beginning of the study. Allocation was established for each patient using a computerized occlusal analysis system. The test implant was the maxillary implant closest to the point of highest occlusal loading. The maxillary implant with least loading was the control implant. Occlusal adjustment was performed using a round diamond burr. This occlusal distribution was verified with the occlusal analysis system. Expression of cytokines from peri-implant crevicular fluid (TNF-α, IL-10, IL-6, IL-1β, IL-8) were recorded and analyzed in both test and control implants before (baseline: T0) and 2 (T1) and 12 months (T2) after occlusal adjustment. The Brunner-Langer non-parametric test was performed.ResultsAt T0, the expression of IL-10 was significantly higher in the test group implants (p = 0.018). Between T0 and T1, the expression of all the cytokines decreased in the implants of both groups with statistically significant differences, except for TNF (p = 0.271). When comparing both groups at T1, there was no statistically significant difference in any of the analyzed cytokines. At T2, TNF-α suffered when compared with baseline, a statistical decrease in both study and control implants (p < 0,001). At T2, there were no statistically significant differences between groups in any of the cytokines analyzed.ConclusionsImplants with higher occlusal load presented higher expression of IL-10 in peri-implant crevicular fluid. Occlusal adjustment produced a decrease in the expression of all the analyzed cytokines, both in test and control implants.

Microrelief of Rounded Diamond Crystals as an Indicator of the Redox Conditions of Their Resorption in a Kimberlite Melt

We conducted a detailed study of the morphology of diamond crystals partially dissolved in a water-bearing kimberlite melt at pressure of 6.3 GPa, temperature of 1400 °C, and two oxygen fugacities (fO2) corresponding to the Re-ReO2 buffer and near the magnetite–hematite (MH) buffer. The triangular etch pits on the {111} faces, which formed during experimental diamond dissolution, were found to completely correspond to negative trigons on natural diamond crystals in the shape and sidewalls inclination angle. Furthermore, two experimental fO2 values were associated with two relief types of the rounded tetrahexahedroid surfaces typical of natural rounded diamonds. Therefore, the surface microrelief on rounded natural diamond crystals was concluded to be an indicator of the redox conditions of natural diamond resorption.