Background: Optical impairments
of teeth in the esthetic zone constitute a
the problem for many dentists and patients as several studies concluded that
patients were dissatisfied with their dental appearance because of their
restorations’ color. The purpose of this study was to assess patient satisfaction
combined with shade matching of VITA SUPRINITY versus lithium disilicate
(IPS e-max CAD) all-ceramic crowns in the esthetic zone.
Methods: 26 patients with teeth problems indicated for full coverage
restoration on one tooth in the esthetic zone (from upper central incisor to 1
premolar) were randomized into 2 equal groups (n=13) for which different
CAD-CAM ceramic materials were used; (VITA SUPRINITY) a zirconia
reinforced lithium silicate ceramic and (IPS e.max CAD) lithium disilicate glass
ceramic. The crowns were fabricated to match the shade of the contra-lateral/
adjacent tooth and assessed using the modified USPHS criteria. Also patient
satisfaction was assessed. The data obtained by evaluating each assessment
criteria were statistically analyzed using the Chi-square test that was performed
in categorical data.
In dentistry, accurate and predictable shade matching between natural teeth and restorative materials represents a challenge for clinicians and laboratory technicians. For decades, visual shade matching was most commonly used for shade selection in dental clinics as it is easy and does not require expensive equipment1,2. Several studies reported that the color of the shade tabs is uniformly distributed and the shade guide enables accurate shade matching with the natural teeth3,4. Other studies stated that the number of correct matches might increase if the Vitapan 3D-Master shade guide is used4–6. They also suggested the use of Vitapan 3D-Master along with shade mapping, as in this study, to allow the exclusion of the effect of operators’ experience on the shade-matching process and to ensure the correct placement of different shade effects and characterizations4–6.
However, many factors may negatively affect the quality of shade matching clinically, including tooth texture, lighting conditions, the surroundings, and background7, as well as the subjective nature of human color observation, through color blindness or color perception defects8,9. Differences in gender10, variations in the experience of the evaluators, lighting conditions, metamerism, and eye fatigue that could affect proper shade selection11. Additionally, factors such as tooth dehydration as a result of prolonged clinical procedures12 and color alteration of shade tabs after chemical disinfection can cast a significant effect on the final shade matching13–15. Therefore, in order to eliminate the confounders during the
color-matching process, instrumental methods have been introduced16. A greater correlation in several studies has been found between the objective (spectrophotometer) and the subjective (visual) shade selection methods with respect to the color dimension of value or lightness, followed by hue and chroma17–19. It was concluded that a combination of both methods should be used for a successful esthetic outcome. While other studies found that using a spectrophotometer for shade matching is more accurate than using a conventional shade guide20–24. In other studies, instrumental color matching was suggested as a supplementary tool for a better esthetic outcome18,19,22. In addition, the final color of all-ceramic restorations is affected by different factors including the porcelain layering technique25,
dental ceramic type, ceramic brand26, veneering ceramic thickness27–29, and firing temperature and conditions30–32. Moreover, clinical parameters, including type 33, color 34, and thickness 35,36 of cement can also influence the final result37. Therefore, the esthetic needs of the patients during treatment should be taken into consideration, otherwise, patient satisfaction will not be achieved, which has a significant effect on patient self-perception and quality of life38,39. A survey looking at patient satisfaction with esthetic treatment found that the restoration color was the primary cause for patient dissatisfaction, as 89.3% of patients were not satisfied with their esthetic treatment because of the color of their restoration40. Other studies found that tooth color and gender also affect patient satisfaction, with females
more dissatisfied than males41,42.
Newly introduced ceramic systems with improved optical properties may lead to improve clinical shade matching and patient satisfaction. VITA SUPRINITY, presented by VITA Zahnfabrik, is a glass ceramic material enriched with approximately 10% zirconia by weight. This fine homogenous dual microstructure resulted in high flexural strength while simultaneously providing a high percentage of glassy matrices. These structural effects provide the ceramic with good optical and polishing properties and allow delivery of restorations with excellent
esthetics43,44. Lithium disilicate ceramic (such as IPS e.max CAD, manufactured by Ivoclar Vivadent) is considered one of the more esthetic ceramics due to the glass matrix embedded with needle-like lithium
disilicate crystals that results in the reduction of internal scattering of the light as it passes through the material. There are also other optical properties for better mimicking adjacent natural teeth, which include the chameleon effect45,46.
Therefore, this study was conducted to evaluate patient satisfaction according to the visual analog scale (VAS) and shade matching of VITA SUPRINITY versus (IPS e-max CAD) lithium disilicate all ceramic crowns in the esthetic zone using the modified United States Public Health Service (USPHS) criteria in a prospective controlled randomized clinical trial. The null hypothesis of the study was that there would be a difference in patient satisfaction and shade matching of VITA SUPRINITY if compared with lithium disilicate ceramic crown used in the esthetic zone.
Clinical evaluation:
Patients were given a handheld mirror to view their teeth and definitive restoration in the clinic and evaluated their own
restoration57. Patients were asked to fill in a patient satisfaction chart for either satisfaction or dissatisfaction.
In addition, restorations were evaluated by three prosthodontists from the Department of Fixed Prosthodontics, at Cairo University. A few minutes before the procedure, these evaluators entered the clinic in order to adapt to the environmental lighting conditions51,54,57,59–61. The evaluation was performed with the same
sequence used for initial shade-matching (visually using VITA 3D-Master shade guide system (VITA, Zahnfabrik, Germany) in accordance to the contra-lateral/adjacent tooth under different light conditions (natural daylight, incandescent light, and color corrected light). To avoid eye fatigue, evaluators were asked to rest their eyes by temporarily closing them or looking at a neutral grey zone every 10 seconds5,18. Evaluators were asked to fill in a clinical assessment chart with each patient number. Primary outcome (patient satisfaction) The two groups of patients were assessed using the Visual Analogue Scale (VAS)40,42,57 which is binary and documented in the chart including a number of satisfied and unsatisfied.
Results: According to the modified USPHS criteria, 100% of the patients were Alpha scores with 0% for Bravo, Charlie, and Delta scores in both groups. While according to the visual analog scale (VAS), 100% of the patients were
satisfied while 0% were dissatisfied with the restoration in both groups. Conclusions: The results for both materials in terms of patient satisfaction and shade matching were Alpha. This indicated that both materials are clinically accepted to be used as full coverage restorations for excellent esthetic outcome.
Data availability:
