Explaining the colour of natural healthy gingiva.

To examine the differences between natural gingival colour in men and women. To determine the degree of predictability of changes in the gingival colour coordinates recorded for healthy gingiva, according to age, long-term medication, frequency of toothbrushing, and smoking habits. The CIELAB colour coordinates were recorded using a spectrophotometer for 360 Caucasian adult participants (aged 18-92 years), in three zones of the healthy attached gingiva of the maxillary central incisor. Regression models were created for each zone and each sex, taking the L*, a* and b* coordinates as dependent variables and age, frequency of toothbrushing, smoking habits (0-non-smoker; 1-smoker) and whether participants were taking long-term medication (0-no; 1-yes) as independent variables. The statistical analysis was conducted with SPSS version 26.0, using multiple regression models. Statistically significant differences between men and women were found only for colour coordinate b*, in all three zones. The only colour coordinate on which the predictor variables had a significant effect was the L* coordinate. In men, age and long-term medication had the greatest effect as predictors (maximum R2 = 0.149). In women, frequency of toothbrushing was the strongest predictor in the predictive models (maximum R2 = 0.099). The colour of gingiva in men contained a larger amount of blue, given that significantly lower values for colour coordinate b* were recorded in men than women, although this difference lacked clinical implications. For both sexes, the regression models produced had a modest predictive capacity. The L* coordinate was the dependent variable that showed the greatest predictability.

Three-dimensional representation of the Vita Toothguide 3D-Master: An in vivo clinical study.

STATEMENT OF PROBLEM: The Vita Toothguide 3D-Master (Vita Zahnfabrik) is considered the dental shade guide in which the three dimensions of color - lightness, hue, and chroma - are most well-ordered in the CIELAB color space. No research has yet explored how well the Vita Toothguide 3D-Master is ordered in the 3D color space by recording color coordinates in vivo. PURPOSE: To evaluate the spatial color distribution of the Vita Toothguide 3D-Master's lightness, chroma, and hue groups and its 26 physical shade tabs. MATERIALS AND METHODS: The dental color (L*, C*, h°, a*, and b* color coordinates) of a healthy maxillary central incisor was recorded for 1361 participants (aged between 18 and 89 years) using a Vita Easyshade Compact spectrophotometer (Vita Zahnfabrik). The R 2.7.2. statistics program was used to create the visual representations. RESULTS: The five lightness levels are those that are best distributed in the color space, in relation to the L* coordinates, followed by the chroma group and, finally, the hue group. The 5M1, 5M2, and 5M3 physical shade tabs are situated at a greater distance apart from the other tabs in the color space. CONCLUSIONS: The Vita Toothguide 3D-Master's 26 physical shade tabs are satisfactorily distributed in three-dimensional space, although strict mathematical criteria are not followed. The natural dental shades that fall lower on the lightness scale are the most poorly represented by the physical shade tabs. CLINICAL IMPLICATIONS: Darker teeth are poorly represented by the Vita Toothguide 3D-Master's physical shade tabs. The spatial distribution of dental shade guides needs to be improved to ensure they provide homogeneous coverage of the entire chromatic spectrum corresponding to natural teeth. This would help reduce the errors inherent to the subjective visual color selection process.

Comparison of surface roughness of additively manufactured implant-supported interim crowns fabricated with different print orientations.

PURPOSE: To assess the influence of print orientation on the surface roughness of implant-supported interim crowns manufactured by using digital light processing (DLP) 3D printing procedures. MATERIALS AND METHODS: An implant-supported maxillary right premolar full-contour crown was obtained. The interim restoration design was used to fabricate 30 specimens with 3 print orientations (0, 45, and 90 degrees) using an interim resin material (GC Temp PRINT) and a DLP printer (Asiga MAX UV) (n = 10). The specimens were manufactured, and each was cemented to an implant abutment with autopolymerizing composite resin cement (Multilink Hybrid Abutment). Surface roughness was assessed on the buccal surface of the premolar specimen by using an optical measurement system (InfiniteFocusG5 plus). The data were analyzed with a Shapiro-Wilk test, resulting in a normal distribution. One-way ANOVA and the Tukey HSD tests were selected (α = 0.05). RESULTS: Statistically significant discrepancies were found in the surface roughness mean values among the groups tested (p < 0.001). The lowest mean ± standard deviation surface roughness was found with the 90-degree group (1.2 ± 0.36 µm), followed by the 0-degree orientation (2.23 ± 0.18 µm) and the 45-degree group (3.18 ± 0.31 µm). CONCLUSIONS: Print orientation parameter significantly impacted the surface roughness of the implant-supported interim crowns manufactured by using the additive procedures tested.

Fe3O4-SiO2 Mesoporous Core/Shell Nanoparticles for Magnetic Field-Induced Ibuprofen-Controlled Release.

Hybrid magnetic nanoparticles made up of an iron oxide, Fe3O4, core and a mesoporous SiO2 shell with high magnetization and a large surface area were proposed as an efficient drug delivery platform. The core/shell structure was synthesized by two seed-mediated growth steps combining solvothermal and sol-gel approaches and using organic molecules as a porous scaffolding template. The system presents a mean particle diameter of 30(5) nm (9 nm magnetic core diameter and 10 nm silica shell thickness) with superparamagnetic behavior, saturation magnetization of 32 emu/g, and a significant AC magnetic-field-induced heating response (SAR = 63 W/gFe3O4, measured at an amplitude of 400 Oe and a frequency of 307 kHz). Using ibuprofen as a model drug, the specific surface area (231 m2/g) of the porous structure exhibits a high molecule loading capacity (10 wt %), and controlled drug release efficiency (67%) can be achieved using the external AC magnetic field for short time periods (5 min), showing faster and higher drug desorption compared to that of similar stimulus-responsive iron oxide-based nanocarriers. In addition, it is demonstrated that the magnetic field-induced drug release shows higher efficiency compared to that of the sustained release at fixed temperatures (47 and 53% for 37 and 42 °C, respectively), considering that the maximum temperature reached during the exposure to the magnetic field is well below (31 °C). Therefore, it can be hypothesized that short periods of exposure to the oscillating field induce much greater heating within the nanoparticles than in the external solution.

Study of attached gingiva space color according to gender and age in Caucasian population.

OBJECTIVE: To describe the color of the healthy attached gingiva adjacent to the maxillary incisors and to evaluate the effect of age and gender on CIELAB color coordinates. MATERIALS AND METHODS: The study included 216 Caucasian individuals (129 females and 87 males) divided into three age groups. A SpectroShade Micro spectrophotometer was used to register color coordinates at 2.5 mm apical of the zenith of the upper central incisors. Descriptive and inferential statistical analysis was performed. RESULTS: The minimum and maximum coordinates in which the CIELAB natural gingival space is delimited are: L* minimum 40.4 - L* maximum 61.2; a* minimum 17.0 - a* maximum 30.2; b* minimum 9.8 - and b* maximum 21.9. There are statistically significant differences between males and females for coordinates L*, a* and b* in the attached gingival area selected. Age had a significant effect on coordinate b* (p = 0.000). CONCLUSIONS: Statistically significant differences were found between the L*, a* and b* color coordinates of the attached gingiva between men and women, although the color difference is below the clinical acceptance threshold. The attached gingiva takes on a bluish color as the patients get older, which means that the b* coordinate decreases. CLINICAL SIGNIFICANCE: With a prosthodontic approach, knowledge of the CIELAB natural attached gingival coordinates based on the patient's age and gender will facilitate the clinician's work in selecting the appropriate color. The CIELAB system values found can be used as a gingival shade guide reference.

Coverage error and shade-match accuracy in three ceramic gingival systems.

STATEMENT OF PROBLEM: Research into the coverage error (CE) of gingival systems that have been expanded by using ceramic specimens created by mixing basic colors is lacking. PURPOSE: The purpose of this in vitro study was to compare the CEs of 3 ceramic gingival color systems that have been expanded with basic-color mixtures from a sample of 360 White participants and to classify the participants according to the accuracy of the shade match achieved with each system. MATERIAL AND METHODS: L*a*b* color coordinates were recorded in 3 zones of attached gingiva for 360 White participants with healthy gingival tissue (187 men and 173 women). The CEs were calculated for 3 ceramic gingival systems that had been expanded with specimens obtained by mixing the basic colors in consecutive order, the color percentages in each mixture having been altered by 10% increments. The systems were Heraceram (Kulzer GmbH) (n=51); Vita VM9 (Vita-Zahnfabrik) (n=41); and IPS Style (Ivoclar AG) (n=41). The participants were classified into 3 groups according to how well the selected shade matched their gingival color (excellent, acceptable, or poor). The data were analyzed using a 1-way ANOVA with a randomized block design and the homogeneity of proportions test (α=.05). RESULTS: Statistically significant differences were found between the CEs of the 3 expanded gingival systems in the 3 zones where gingival color was measured (P<.001). The expanded Heraceram system had the smallest CE (ΔE00: minimum 2.66 in the middle zone and maximum 2.95 at the mucogingival line). In the 3 gingival zones, the expanded IPS Style system produced the largest percentage of participants with a poor shade match (ΔE00: minimum 71.4% at the mucogingival line and maximum 75.8% at the free gingival margin), while the expanded Heraceram system had the lowest percentage of participants with a poor shade match (ΔE00: minimum 33.3% in the middle zone and maximum 41.7% at the mucogingival line). CONCLUSIONS: The CEs calculated for the expanded Vita VM9 and IPS Style ceramic gingival color systems exceeded the clinical acceptability thresholds in the 3 zones examined. According to the ΔE00 formula, the gingival color of at least 33% of participants matched poorly with the expanded systems studied.

Techniques to improve the accuracy of complete arch implant intraoral digital scans: A systematic review.

STATEMENT OF PROBLEM: The best method of optimizing the accuracy of complete arch intraoral digital scans is still unclear. For instance, the location of the scan bodies can be significantly distorted with respect to their actual positions, which would lead to a nonpassive fit of the definitive prosthesis. PURPOSE: The purpose of this systematic review was to analyze available techniques for improving the accuracy of digital scans in implant-supported complete arch fixed prostheses. MATERIAL AND METHODS: Three databases (Medline, Embase, and Google Scholar) were searched, and the results obtained were supplemented by a hand search. Specific descriptors identified techniques whose objective were to increase the accuracy of digital scans in implant-supported complete arch fixed prostheses. Titles and abstracts were screened by 2 independent reviewers, and unclear results were discussed with a third independent reviewer. A qualitative analysis based on procedural parameters was used. The interexaminer agreements of both were assessed by the Cohen kappa statistic, and the Risk of Bias Tool was used to assess the risk of bias across the studies. RESULTS: A total of 17 techniques matching the inclusion criteria were evaluated. Higher accuracy but also differences regarding the need for supplementary devices, number of intraoral scans, and time consumption of clinical and software program steps were observed compared with the conventional digital scanning protocol. The use of a splinting device was common to most of the studies. The outcome variables for the evaluation of the effectiveness of these protocols were heterogeneous. CONCLUSIONS: The use of additional techniques during intraoral scanning can improve accuracy in implant-supported complete arch fixed prostheses. However, higher complexity for those procedures should be expected.

Magnetic Fe/Fe3C@C Nanoadsorbents for Efficient Cr (VI) Removal.

Magnetic carbon nanocomposites (α-Fe/Fe3C@C) synthesized employing fructose and Fe3O4 magnetite nanoparticles as the carbon and iron precursors, respectively, are analyzed and applied for the removal of Cr (VI). Initial citric acid-coated magnetite nanoparticles, obtained through the co-precipitation method, were mixed with fructose (weight ratio 1:2) and thermally treated at different annealing temperatures (Tann = 400, 600, 800, and 1000 °C). The thermal decomposition of the carbon matrix and the Fe3O4 reduction was followed by thermogravimetry (TGA) and Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction, Raman spectroscopy, SQUID magnetometry, and N2 adsorption-desorption isotherms. A high annealing temperature (Tann = 800 °C) leads to optimum magnetic adsorbents (high magnetization enabling the magnetic separation of the adsorbent from the aqueous media and large specific surface area to enhance the pollutant adsorption process). Cr (VI) adsorption tests, performed under weak acid environments (pH = 6) and low pollutant concentrations (1 mg/L), confirm the Cr removal ability and reusability after consecutive adsorption cycles. Physical adsorption (pseudo-first-order kinetics model) and multilayer adsorption (Freundlich isotherm model) characterize the Cr (VI) absorption phenomena and support the enhanced adsorption capability of the synthesized nanostructures.

Dental student, dentist, dental assistant, and layperson perception of pink gingival porcelain color.

STATEMENT OF PROBLEM: How pink gingival porcelain color is perceived by participants classified according to profession and sex is unclear. PURPOSE: The purpose of this in vitro study was to evaluate the degree of correlation between the ordering of color tabs by participants classified according to profession, years of dental work experience, and sex and the ideal chromatic order based on the color coordinate L∗ (lightness). MATERIAL AND METHODS: Twenty-one colored specimens made of Heraceram pink gingival porcelain were used. A group of 352 participants (118 men and 234 women) comprised of dental students (n=126), dentists (n=54), dental assistants (n=56), and laypersons (n=116) were enrolled. They were asked to order the specimens starting from the lightest to the darkest. The Kendall coefficients of concordance W and correlation T were used to determine whether the individuals in each experimental group rating the specimens were consistent and accurate. RESULTS: The degree of agreement between the ideal ordering and that carried out by the participants within the different professional categories was greater than 0.8 in all assessments. No statistically significant differences were found among the groups in relation to professional category, work experience, or sex (P>.05). The Kendall coefficients were higher in the ranking of the darker specimens for all groups of participants. CONCLUSIONS: No statistically significant differences were found among dentists, dental assistants, dental students, and laypersons in the arrangement of pink porcelain specimens according to their lightness. In addition, in all groups, the darker gingival specimens were ordered significantly better according to their lightness than the lighter specimens.

Influence of implant angulation and clinical implant scan body height on the accuracy of complete arch intraoral digital scans.

STATEMENT OF PROBLEM: The accuracy of digital implant scans can be affected by the implant angulation, implant depth, or interimplant distance. However, studies analyzing intraoral scanning accuracy with different implant angulations and different scan body heights are scarce. PURPOSE: The purpose of this in vitro study was to determine the influence of the implant angulation and clinical implant scan body height on the accuracy of complete arch scans. MATERIAL AND METHODS: Two definitive implant casts with 6 implant analogs (Zimmer Biomet) were obtained: 1 cast had all the implant analogs parallel (GP group), and 1 cast had the implant analogs with divergence of up to 30 degrees (GD group). A coordinate measurement machine (Global Evo 09.15.08) was used to measure the positions of the implant analogs. Each group was divided into 3 subgroups depending on the clinical implant scan body height: 10, 6, and 3 mm. An implant scan body (Elos Accurate Scan Body Brånemark system) was positioned on each implant analog. A total of 10 scans of each subgroup were recorded by using an intraoral scanner (TRIOS 3). Each STL file obtained was imported into a reverse engineering software program (Geomagic), and linear and angular Euclidean measurements were obtained. The Euclidean calculations between the implant analog positions of the definitive implant casts were used as a reference to calculate the discrepancies among the corresponding subgroups. The Kolmogorov-Smirnov test revealed that the lineal measurements were not normally distributed, so the Kruskal-Wallis and pairwise comparison Dunn tests were used (α=.05). The Kolmogorov-Smirnov test revealed that the angular measurements were normally distributed. Therefore, the 2-way ANOVA and pairwise comparison Tukey tests were used (α=.05). RESULTS: The Kruskal-Wallis test revealed significant differences in the linear Euclidean medians between the GP and GD groups with different clinical implant scan body heights (H(5)=23.18, P<.001). Significant differences in the linear Euclidean medians were computed between the GP-6 and GD-10 subgroups (P=.009), GD-3 and GD-6 subgroups (P=.029), and GD-3 and GD-10 subgroups (P=.001). Two-way ANOVA revealed that the implant angulation (F(1, 3.3437)=28.93, P<.001) and clinical implant scan body height (F(2, 0.4358)=3.77, P=.029) were significant predictors of discrepancies in the angular measurement. CONCLUSIONS: Implant angulation and clinical scan body height influenced scanning accuracy. The lowest clinical implant scan body height tested had the lowest accuracy in both parallel and angulated implants, but statistically significant differences were found only in the angulated group.

Intraoral Digital Scans for Fabricating Tooth-Supported Prostheses Using a Custom Intraoral Scan Body.

This article describes a technique to assist with intraoral digital scans for fabricating tooth-supported prostheses by using a custom intraoral scan body when the extension of the scan or the clinical characteristics might compromise the reliability of the intraoral digital scan. A preliminary intraoral scan of the tooth preparations is used to design a custom intraoral scan body which is manufactured using polymethylmethacrylate and a 5-axis milling machine. A low-viscosity polyvinyl siloxane impression of the tooth preparations is obtained using the custom intraoral scan body. Subsequently, the custom intraoral scan body is digitized using an intraoral scanner. A design software program is used to align the digitized custom intraoral scan body with the preliminary intraoral scan to obtain the definitive virtual cast. This technique aims to reduce manual conventional laboratory procedures such as pouring dental impression or die trimming which might minimize inaccuracies on the virtual definitive cast.

3D Master Toothguide Is Adequate to Subjective Shade Selection?

Background and Objectives: To study the validity and the degree of representability of the toothguide 3D Master, with 26 physically shade tabs, on the natural tooth colour on a sample of the Spanish population. Materials and Methods: Natural tooth colour was measured in a sample of 1361 Spanish participants of both genders distributed within an age range of 18 and 89 years of age. The colour coordinates were calculated and the frequency of the 26 physically shade tabs of the toothguide as well as the "intermediate shades" (without physical representation in toothguide) through the Easyshade Compact (Vita-Zahnfabrik) spectrophotometer using the 3D Master System nomenclature. The colour differences between the "intermediate shades" were calculated using the Euclidean formula (ΔEab*). The program used for the present descriptive statistical analysis of the results was SAS 9.1.3. Results: A total of 49 "intermediate shades" were registered in 816 participants (60%). The colour coordinates of the 49 'intermediate shades' cover colour coordinates ranging from 0M1.5 (L* 100.0, C* 7.70, h* 112.2) to 5M2.5 (L* 56.8, C* 35.8, h* 78.5). Not all possible 3D Master System's "intermediate shades" were registered in the population studied. 82.4% of the colour differences among the "intermediate shades" were clinically unacceptable (ΔEab* ≥ 5.5 units). Conclusions: Only 40% of the population studied presented a natural tooth colour belonging to the 3D Master Toothguide's physical shade tabs.

A Combination of a Vibrational Electromagnetic Energy Harvester and a Giant Magnetoimpedance (GMI) Sensor.

An energy harvesting device combined with a giant magnetoimpedance (GMI) sensor is presented to analyze low frequency vibrating systems. An electromagnetic harvester based on magnetic levitation is proposed for the electric power generation. The device is composed of two fixed permanent magnets at both ends of a cylindrical frame, a levitating magnet acting as inertial mass and a pick-up coil to collect the induced electromotive force. At the resonance frequency (10 Hz) a maximum electrical power of 1.4 mW at 0.5 g is generated. Moreover, an amorphous wire was employed as sensor nucleus for the design of a linear accelerometer prototype. The sensor is based on the GMI effect where the impedance changes occur as a consequence of the variations of the effective magnetic field due to an oscillating magnetic element. As a result of the magnet's periodic motion, an amplitude modulated signal (AM) was obtained, its amplitude being proportional to mechanical vibration amplitude (or acceleration). The sensor's response was examined for a simple ferrite magnet under vibration and compared with that obtained for the vibrational energy harvester. As a result of the small amplitudes of vibration, a linear sensor response was obtained that could be employed in the design of low cost and simple accelerometers.

Responsiveness of the different methods for assessing the short-term within-subject change in masticatory function after conventional prosthetic treatments.

STATEMENT OF PROBLEM: Improvement in the masticatory function after replacing missing teeth is one of the main expected outcomes that need to be comprehensively measured with both clinical and patient-centered assessments. An evaluation of the responsiveness of these methods is lacking. PURPOSE: The purpose of this clinical study was to assess the responsiveness of both objective and subjective methods for measuring the impact of different conventional prostheses on masticatory function at prosthesis delivery and 2 months later. MATERIAL AND METHODS: Participants (N=118) requiring prosthetic rehabilitation were selected from patients attending the Faculty of Dentistry of the University of Salamanca. Masticatory function was assessed by means of subjective methods (self-rated ordinal scales, visual analog scale, and food intake ability questionnaire) at baseline and 2 months after treatment. The ability to mix 2-colored chewing gum after 5, 10, and 15 cycles was also evaluated objectively. The responsiveness of each method was categorized by the effect size (ES) as low (<0.5), moderate (0.5 to 0.8), or large (>0.8). RESULTS: The study revealed that in all subgroups, the masticatory function improved 2 months after the treatment. The most responsive method was the visual analog scale (ES: 1.2) and the number of pattern foods perceived to be easily masticated by participants (ES: 0.7 to 1.3). By contrast, the masticatory performance assessed by using the mixing ability test showed a smaller magnitude of change (ES: 0.3 to 0.7). Both the objective and subjective masticatory functions were coherently correlated with age and clinical variables (number of occlusal units or the Eichner index) in all subgroups. However, masticatory performance and masticatory ability were not significantly correlated (r=0.22; P=.12). CONCLUSIONS: Conventional prosthetic treatments significantly improve masticatory function 2 months after delivery, and the subjective methods were the most responsive in assessing changes in participants.

Guided implant scanning: A procedure for improving the accuracy of implant-supported complete-arch fixed dental prostheses.

This article describes a technique to improve the quality of digital intraoral scans for complete-arch prostheses by correcting the cumulative deviations that may arise with conventional digital methods. The approach involves an additional scan in which a reference-marked rigid splint of known dimensions is used to reduce the likelihood of such deviations. The scanned files are sectioned and best fit aligned to generate a more reliable definitive cast and consequently a better-fitting prosthesis.

Comparison of the CIELab and CIEDE 2000 Color Difference Formulas on Gingival Color Space.

PURPOSE: To evaluate the CIELAB and CIEDE2000 formulas to determine which better reflects the difference in color perception, and whether there are gender differences in color perception. MATERIALS AND METHODS: Fifty-six participants grouped 21 different-colored disks made of pink porcelain (color range: from 36.8 to 63.9 for L* , from 16.4 to 35.2 for a* , from 6.2 to 21.6 for b* ), in which the only requirement was that each group be comprised of disks with chromatically indistinguishable colors. Each participant was free to choose the number and composition of the groups. Using the results obtained, a dissimilarity matrix was generated, and nonmetric multidimensional scaling (MDS) was applied to obtain the coordinates of the disks within a Euclidean space. RESULTS: The linear correlation coefficient between the interpoint distances of the MDS configuration (MDS_total sample) and the color differences with the CIELAB formula (ΔE* ab ) was 0.719 (p < 0.001), whereas with the CIEDE2000 formula (ΔE00), it was 0.726 (p < 0.001). For the configuration obtained in the women's group (MDS_w), the correlations between the interpoint distances and the CIELab color difference was 0.720 (p < 0.001), and the CIEDE2000 color differences was 0.730 (p < 0.001). For the configuration obtained in the men's group (MDS_m), the perceived color differences, calculated with both formulas, were less sensitive, 0.670 for CIELab formula and 0.677 for CIEDE2000 formula. CONCLUSIONS: Considering the limitations of this study, the data analyzed indicated that the CIEDE2000 formula reflected the color differences perceived by the human eye similar to the CIELAB formula (ΔE* ab ). Also, women were confirmed to be more sensitive than men to differences in color.

Changes in oral health-related quality of life after three different strategies of implant therapy: a clinical trial.

This research aims to evaluate changes in Oral Health-related Quality of Life (OHQoL) by means of the Oral Impacts on Daily Performances (OIDP) of patients treated with three distinct implant strategies. This clinical trial consisted of an oral examination and a questionnaire-based interview carried out before and after the definitive prosthetic rehabilitation in a consecutive sample of patients requiring dental implants. According to the clinical diagnosis and patient preference, patients were assigned to the one of the following groups: the conventional group (CGCL; n = 40), where implants were inserted without guiding and conventionally loaded; to the guided surgery but conventional loading group (GSCL; n = 35); or to the guided surgery and immediate loading group (GSIL; n = 29). At baseline, the OHQoL was significantly greater among those assigned to CGCL (2.4 ± 1.3) than those assigned to GSCL (3.3 ± 1.3), which were both greater than those patients assigned to GSIL (4.6 ± 2.0). After implant therapy, the oral well-being was significantly better than at baseline, and patient satisfaction was greater when the implants were loaded immediately (8.7 ± 1.1) than if the prosthetic rehabilitation was delayed (8.3 ± 1.1). In the GSIL group, the effect size of the OIDP exceeded the threshold value of 0.8 for all of the OIDP domains and for the total OIDP score and patient satisfaction. A global improvement in the OHQoL scores and patient satisfaction was observed after implant therapy, but the change was markedly greater in the GSIL group.

Clinical study on natural gingival color.

The aims of the study were: to describe the gingival color surrounding the upper incisors in three sites in the keratinized gingiva, analyzing the effect of possible factors which modulate (socio-demographic and behavioral) intersubject variability; to study whether the gingiva color is the same in all three locations and to describe intrasubject color differences in the keratinized gingiva band. Using the CIELAB color system, three reference areas (free gingival margin, keratinized gingival body, and birth or upper part of the keratinized gingiva) were studied in 259 individuals, as well as the related socio-demographic factors, oral habits and the chronic intake of medication. Shadepilot™ spectrophotometer was used. Descriptive and inferential statistical analysis was performed. There are statistically significant differences between males and females for coordinates L* and a* in the middle and free gingival margin. For the b* coordinate, there are differences between males and females in the three locations studied (p < 0.05). The minimum and maximum coordinates in which the CIELAB natural gingival space is delimited are L* minima 28.3, L* maximum 65.4, a* minimum 11.1, a* maximum 37.2, b* minimum 6.9, and b* maximum 25.2*. Age, smoking, and the chronic intake of medication had no significant effect on gum color. There are perceptible color differences within the keratinized gingiva band. These chromatic differences must be taken into account if the prosthetic characterization of gingival tissue is to be considered acceptable. There are significant differences between the color coordinates of the three sites studied in the keratinized gingiva of men and women.

Comparison of two color-difference formulas using the Bland-Altman approach based on gingiva color space.

The objectives of this study were to determine the relationship between the results provided by the classical CIELab (ΔEab*) and the CIEDE2000 (ΔE00) formulas and the gingival color space using the Bland and Altman limits of agreement, to use this relationship to establish the equivalences between the gingival color thresholds of perceptibility of both formulas, and to evaluate whether the relationship between ΔEab* and ΔE00 is modified depending on the axis in which the changes occur. The means of the L*, a*, and b* coordinates of the 21 gingiva porcelain samples (Heraceram, Heraeus Kulzer Mitsui Chemical Groups) were used and the differences in color were calculated in 210 pairs of samples using the CIELab (ΔE*ab) and CIEDE2000 (ΔE00) color-difference formulas. The results obtained with these formulas were compared and the limits of agreement after a logarithmic transformation of the data were obtained. The relationship between both formulas was ln ΔE00 = - 0.22 + ln ΔEab*. The results obtained with the CIELab formula were between 1.01 (95% confidence interval 0.98-1.03) and 1.54 (95% confidence interval 1.52-1.59) times higher than those obtained with the CIEDE200 formula. In the gingiva color space, the scale factor between the CIEDE2000 and CIELab values changes from 0.63 to 1.02, such that providing an accurate scale factor between both values proves difficult. The pairs with the highest ratio were those where the difference in color was mainly due to changes in lightness, whereas the pairs with the smallest ratio were those where the difference in color was mainly due to changes in the blue-yellow or green-red axes.

Interim restoration using dynamic abutments to re-treat a single-implant crown with a labial angulation: A clinical report.

The cause of some peri-implant problems may be primarily attributable to the design of the prosthesis. A screw-retained interim implant may be advisable for reversibility and to avoid peri-implant cement, although screw retention may be difficult for maxillary anterior implants with a labial angulation. In the treatment described, a interim screw-retained crown was attached to a dynamic abutment with a lingual screw access hole to obtain a correctly fitting restoration.