Alhanoof Aldegheishem

Background: Accurate shade selection is essential in restorative and prosthetic dentistry, but visual matching is subjective and influenced by lighting, clinical experience, and color perception. Digital spectrophotometers offer objective, reproducible measurements. Objective: The aim of this study was to compare visual shade selection using the VITA 3D-Master guide by expert practitioners and senior dental students against a digital spectrophotometer (Rayplicker Handy), and to assess inter-examiner consistency within each group. Methods: Five expert practitioners and five senior dental students selected shades (cervical, middle, and incisal thirds) on the maxillary right central incisor in 40 participants, followed by digital measurement. Shade values were converted to CIE Lab* coordinates to compare groups, evaluate inter-examiner consistency, and calculate intraclass correlation coefficients (ICC). Results: Expert–student agreement was close, with small mean ΔE (2.1–2.5 across regions), above the perceptibility threshold (1.2) but within the acceptability threshold and no significant difference (Friedman test, Dunn’s post hoc, p > 0.05 in all regions). Both groups differed markedly from the Rayplicker (mean ΔE 11.9–16.2), exceeding the 50:50% acceptability threshold (ΔE*ab = 2.7) and significantly greater than the expert–student difference (p < 0.001); expert–Rayplicker and student–Rayplicker differences did not differ from each other (p > 0.05). Inter-examiner within-group dispersion was significantly lower (better agreement) among experts than students in the incisal (p < 0.001) and cervical (p = 0.049) thirds, with no difference in the middle third (p = 0.116); intraclass correlation coefficients were directionally higher for experts in all nine region-by-component comparisons, though confidence intervals overlapped between groups and absolute reliability was poor-to-moderate for both. Conclusions: Visual and digital shade selections differed substantially in this study, exceeding the clinically acceptable 50:50% threshold, while expert practitioners and senior students chose comparably close shades to one another using the visual method. However, experts were more internally consistent than students in most regions, suggesting that clinical experience was associated with greater reproducibility, though not necessarily accuracy, of visual shade selection.

Despite the increasing use of additively manufactured restorative materials, comparative information regarding their surface gloss and roughness after different surface treatments and simulated oral challenges remains limited. This study evaluated the gloss and surface roughness of stained and polished 3D-printed resins subjected to acidic storage followed by simulated tooth brushing. Two 3D-printed resins (ONX and Tough 2 [T2]) were compared with a milled material (Lava Ultimate [LU]), which was used as a control. A total of 120 specimens (40 per material) were fabricated, surface-treated (stained or polished), and randomly categorized into acid or water storage/tooth brushing. A gloss meter and non-contact profilometer were used to measure the gloss and surface roughness of the materials. Data analysis was performed using one-way ANOVA, Welch’s pairwise t-tests with Holm adjustment, and HC3-robust Type III factorial models, with significance set at α = 0.05. Gloss significantly decreased, whereas surface roughness (Ra) significantly increased after storage/brushing across the experimental groups (p < 0.05), except for T2 subjected to acid storage/brushing, which showed no significant change in R_a (p = 0.11). Both gloss and R_a were significantly affected by the material type (p < 0.001). For gloss, significant effects of material and surface treatment were observed (p < 0.001). For R_a, significant effects of material, surface treatment, and storage/brushing were detected (p < 0.001). Material type and surface treatment significantly influenced gloss, whereas storage/brushing effect had no significant effect. In contrast, material type, surface treatment, and storage/brushing significantly influenced surface roughness. The milled LU generally exhibited higher gloss and lower roughness than the 3D-printed ONX and T2 materials, particularly among stained specimens, while ONX generally showed more favorable surface properties than T2.

Recent developments in all-ceramic restorative materials have enhanced the clinical applicability of lithium disilicate for aesthetic dental restorations. The current study explores the influence of sintering parameter modulation over the translucency and color change of Amber Mill and IPS e.max CAD ceramics at baseline and following simulated aging through thermocycling and simulated toothbrushing. Sixty discs of lithium disilicate were assigned to two groups according to material type (Amber Mill; E-max), then according to translucency level (HT: high translucency; LT: low translucency). All specimens were sintered, polished, and ultrasonically cleaned in accordance with manufacturer guidelines. Optical properties—including translucency parameter (TP), color difference (ΔE), and color coordinates (L*, a*, b*)—were measured using a spectrophotometer at baseline and after a five-year clinical simulation. Scanning electron microscope (SEM) analysis was performed. Amber Mill-HT demonstrated the highest initial translucency (15.48 ± 0.89), followed by Amber Mill-LT (12.52 ± 0.61). Aging increased TP values in Amber Mill groups, while a slight reduction was observed in E-max groups. Amber Mill-LT exhibited the lowest color change (ΔE = 0.80 ± 0.10), reflecting superior color stability, whereas E-max-LT showed the highest ΔE (1.43 ± 0.21). SEM analysis demonstrated distinct microstructural differences between materials and translucency levels. High-translucency ceramics exhibited finer, more uniform lithium disilicate crystals and continuous glassy matrices, whereas low-translucency groups showed larger crystals, increased heterogeneity, and greater surface irregularities after aging. Overall, Amber Mill-LT displayed the greatest color stability, whereas E-max groupsretained translucency more consistently. All evaluated ceramics showed optical alterations within clinically acceptable limits, confirming their suitability for aesthetic restorative applications.

This study investigates the effect of different sintering parameters on the surface roughness and fracture resistance of different CAD/CAM lithium disilicate ceramics before and after thermocycling and simulated toothbrushing. Sixty lithium disilicate ceramic samples were categorized according to ceramic type (AMB: Amber Mill, ECAD: IPS e.max CAD) and level of translucency (LT: low and HT: high) into four groups: AMB_LT, AMB_HT, ECAD_LT and ECAD_HT. Specimens were prepared to 2 mm thickness, crystallized, polished, and subjected to thermocycling to simulate five years of clinical aging. Simulated toothbrushing was performed using a soft-bristled mechanical brushing system under controlled force and strokes. Surface roughness was assessed using a profilometer before and after brushing, and fracture resistance was measured using a universal testing machine. Data were statistically evaluated using paired t-tests, one-way ANOVA with Bonferroni post hoc correction (p ≤ 0.05). LT lithium disilicate specimens exhibited significantly smoother surfaces than high-translucency counterparts. After thermocycling and brushing simulation, all groups showed a statistically significant increase in surface roughness, ranging between 0.239 ± 0.012 μm (AMB_LT) and 0.486 ± 0.014 μm (ECAD_HT). In terms of fracture resistance, the highest values were recorded for ECAD_HT (636 ± 8.29 N), and the lowest in the AMB_HT group (546.3 ± 21.9 N) with significant differences observed between materials and translucency levels. Sintering parameters and artificial aging significantly influenced the surface roughness and fracture resistance of lithium disilicate ceramics. Low-translucency variants demonstrated smoother surfaces and higher strength than high-translucency groups, while all materials exhibited increased roughness after aging. These findings provide guidance for the selection of lithium disilicate ceramics, balancing esthetic and mechanical requirements in anterior and posterior restorations.

This study evaluated the effect of acidic environment and tooth brushing on the color stability and translucency of stained 3D-printed ceramic-reinforced composite (CRC) resins for indirect restorations and hybrid prostheses. Twelve specimens were prepared from each 3D-printing resin material: Ceramic Crown (CC), OnX (ONX), and Tough 2 (T2), and one CAD/CAM milling resin, Lava Ultimate (LU). After preparation, all specimens were stained, then immersed in either water or citric acid. Subsequently, the specimens underwent simulated tooth brushing for 3650 cycles. Color stability (ΔE) and translucency parameter (TP) were measured using a spectrophotometer. Data were analyzed using ANOVA, post hoc Tukey tests, and independent Student t-tests (α = 0.05). Material type, immersion medium, and their interaction did not significantly influence the mean ΔE (p > 0.05). The lowest ΔE value was for LU in acid (ΔE = 1.11 ± 0.39), and the highest for T2 in water (ΔE = 2.09 ± 1.47). Except for ONX and LU in acid, all materials had ΔE values above the perceptibility threshold (ΔE = 1.2). The mean TP was significantly affected by material type, immersion medium, and their interaction (p < 0.05). The lowest TP value was for group CC in acid (0.91 ± 0.26); the highest was for group LU in acid (6.24 ± 0.56). After immersion and subsequent tooth brushing, TP values decreased for all materials. Exposure to an acidic environment and tooth brushing did not affect color stability but significantly reduced translucency. Both the 3D-printed CRCs and milled resin material displayed comparable color stability below clinically acceptable thresholds, though the translucency of 3D-printed materials remained lower compared to milled material.

This study aimed to assess the effect of acidic storage and simulated brushing on the translucency and color stability of 3D-printed resins for prosthodontic applications. Three 3D printed resin materials—Ceramic Crown (CC), OnX (ONX), and Tough 2 (T2)—were compared with a CAD/CAM milled nano-ceramic resin material (Lava Ultimate, LU). Twelve specimens were fabricated from each material and were allocated into two groups based on the storage medium (water or citric acid), followed by simulated tooth brushing for 3650 cycles. The specimens’ translucency (TP) and color stability (ΔE) were determined using a spectrophotometer. The data was compared using ANOVA, independent student t-tests, and a post hoc Tukey test (p < 0.05). Multiple comparisons of mean differences in TP revealed significant differences between the tested materials (p < 0.001), except for groups CC and ONX. Irrespective of the groups, all materials showed decreased TP values after simulated tooth brushing. Regarding color stability, CC (0.66 ± 0.42) and T2 (1.40 ± 0.34) in acid demonstrated the least and greatest color changes, respectively. The ΔE did not vary between the materials or between the storage media (p > 0.05). Except for T2 and LU in water, the other materials showed ΔE values below the perceptibility threshold of 1.2. The material type and storage media affected the translucency of the tested materials. However, regardless of the material type and storage media, there was no discernible impact on the color change of the tested materials.

Achieving accurate fit in implant-supported prostheses is critical for avoiding mechanical complications; however, the influence of digital manufacturing techniques and abutment designs on misfit and preload remains unclear. This study evaluated the impact of different manufacturing techniques (CAD-cast and 3D printing) and abutment connection types (engaging [E], non-engaging [NE]) on the misfit and preload of implant-supported cantilevered fixed dental prostheses (ICFDPs). Misfit was measured at six points using scanning electron microscopy, and preload was assessed via eight strain gauges placed buccally and lingually on four implants. Frameworks were torqued to 35 Ncm, retorqued after 10 min, and subjected to 200,000 cycles of loading. Mean preload values ranged from 173.4 ± 79.5 Ncm (PF) to 330 ± 253.2 Ncm (3DP). Preload trends varied depending on the abutment type and manufacturing technique, with the 3DP group showing higher preload in engaging (E) abutments, whereas the CAD-cast group showed the opposite pattern. Although preload values varied numerically, these differences were not statistically significant (p = 0.5). In terms of misfit, significant differences were observed between groups (p < 0.05), except between CAD-cast E (86.4 ± 17.8 μm) and 3DP E (84.1 ± 19.2 μm). Additionally, E and NE abutments showed significant differences in misfit within both CAD-cast and 3DP groups. Overall, 3DP frameworks showed superior fit over CAD-cast. These findings suggest that 3DP may offer improved clinical outcomes in terms of implant–abutment fit.

Dentine adhesives have demonstrated great success with permanent teeth. Though the results in primary teeth are not well documented, some studies have demonstrated lower values of bond strength in primary teeth than those found in permanent teeth. The aim of this study was to compare and evaluate the effect of grape seed extract (6.5%) (Herbal Bio Solutions, Delhi, India), glutaraldehyde (5%) (Loba Chemie PVT. LTD., Mumbai), hesperidin (0.5%) (Herbal Bio Solutions, Delhi, India), and casein phosphopeptide-amorphous calcium phosphate (tooth mousse) (GC Corporation, Alsip, IL, USA) on the shear bond strength of dentine of primary teeth and to evaluate the resin tags at the resin tooth interface. Seventy-five caries-free human primary molars were collected, and their occlusal surfaces were ground flat. Dentin surfaces were etched using phosphoric acid. Then teeth were randomly assigned in sequential order to five groups according to the dentinal treatment method: Group I (Control group) (no treatment), Group II (5% glutaraldehyde), Group III (6.5% grape seed extract), Group IV (0.5% hesperidin), and Group V (CPP-ACP). Ten teeth from each group were assigned for Shear Bond Strength and five for SEM analysis. ANOVA and a post hoc least significant difference test (p < 0.05) were used for statistical analysis of the collected data. The grape seed extract group showed significantly increased shear bond strength than the control group (p < 0.05), and the mean length of resin tags in different dentine bio modifiers groups was also statistically significant (p < 0.05). The use of dentin bio modifiers such as 5% glutaraldehyde, 6.5% grape seed extract, 0.5% hesperidin, and CPP-ACP in the bonding process for primary teeth did not improve the dentinal bond strength.

Purpose. The aim of this in vitro study was to evaluate the fracture resistance and type of failure of two adhesive fiber post systems used to restore endodontically treated teeth. Material and Methods. Twenty‐seven extracted premolars were selected and divided into three groups (n = 9): a control group restored with direct composite core (group 1), teeth restored with single fiberglass posts (group 2), and teeth were restored with multifiber posts (Biolight Plus System) (group 3). Fracture resistance was measured by applying axial compressive loads parallel to the longitudinal axis of the tooth until failure. Data was analyzed with one‐way ANOVA followed by post hoc Turkey tests. Results. The results showed that the mean forces to failure of the control group (0.068 kN) were significantly lower than those restored with either fiberglass post systems (p = 0.013). There was no significant difference between the multifiber and the single fiberglass post system in terms of resistance to fracture (p = 0.097). Although there are more teeth fractured favorably (above the CEJ) in the Biolight Plus group (77.7%) compared to both the control and fiberglass post groups, it was not statistically significant (p = 0.226). Conclusion. Within the limitations of this study, restoring endodontically treated with a multifiber post system is an adequate alternative to single fiberglass post system in terms of resistance to fracture.