A comparison of intraoral spectrophotometers-Are there user-specific differences?

OBJECTIVE: The objective of this study was to determine the potential impact of a positioning splint on the determination of the correct tooth color using VITA Easyshade 4 (VE4) or VITA Easyshade 5 (VE5) (VITA Zahnfabrik, Germany). MATERIALS AND METHODS: Dental students (n = 50) in their third year and one expert determined the tooth shade of an extracted human tooth using VE4 and VE5, in presence or absence of a positioning splint. The determined shade values (L*a*b*) were collected and the delta E was calculated. A statistical evaluation was performed with the program SPSS® (P < .05). RESULTS: There was no significant difference in the determination of the correct tooth color (VITA 3D-Master shade), independent from either the expert or the students positioning splint, and independent of using VE4 (P = 1; P = .092) or VE5 (P = .125; P = .25). CONCLUSION: Using VE4 or VE5, a positioning splint has no effect on the determination of the correct tooth color (VITA 3D-Master shade). For an exact measurement of the L*a*b values in clinical studies, a positioning splint should be used. A person untrained in working with the devices can determine the correct tooth shade more frequently with VE5 than with VE4.© 2018 Wiley Periodicals, Inc. CLINICAL SIGNIFICANCE: Correctly determining the tooth shade is an essential treatment step in esthetic reconstructive dentistry. Color is probably one of the most important determinants of esthetics in dentistry. Factors such as lighting conditions, gender, age, experience, and color vision impairment affect the process of shade matching. These deficits brought about the desire for an objective and reproducible shade determination method with digital devices for shade determination. One of the most proven and frequently used digital shade determination devices is the "VITA Easyshade" (VITA Zahnfabrik, Bad Säckingen, Germany). At this point in time, there are no (published) reports on the measurement accuracy of the new VE 5. In addition, there are, as of yet, no investigations comparing the VE 4 and VE 5.

Influence of tongue position on the determination of tooth shade.

STATEMENT OF PROBLEM: Dentists frequently use electronic devices to determine tooth color. However, neither the instructions for these devices nor the accompanying brochures refer to the environmental conditions required at the point of measurement. PURPOSE: The purpose of this multicenter prospective clinical study was to reveal whether a change in the oral background influences tooth color determination. MATERIAL AND METHODS: Students (N=42) at the dental clinic in Berlin, Leipzig, Greifswald and Olomouc (women n=27, men n=15) participated in this study. It was their first contact with the spectral photometer (Easyshade Advance 4.0; VITA Zahnfabrik). After a short introduction on how to use the device, the students made 1-point measurements on the same patient on the maxillary central incisor. In the first measurement, the patient's mouth was open, and the palatal surface uncovered. In the second measurement, the patient's mouth was closed slightly, and the tongue pressed on the lingual surface of the maxillary central incisor. The mean ±SD and the 95% confidence interval (95 % CI) were calculated using the Student t test for each test series (α=.05). RESULTS: Statistical evaluation of the 2 measurements revealed changes in the L*a*b* values with a mean L*=0.204, a*=-0.351, and b*=0.02; a median of 0.4, -0.3, and -0.1, respectively; a ±SD of 2.37, 0.64, and 0.89, respectively; and 95% CIs of L*=-0.476 to 0.884, a*=-0.531 to -0.702, and b*=-0.23 to 0.52, respectively. These differences were not statistically significant (P>.05). The measurements of L*, a*, and b* with and without tongue coverage of the lingual surfaces of the maxillary teeth did not show any statistically significant differences (P=.663). CONCLUSIONS: The results demonstrate that the position of the tongue does not influence measurement accuracy during the application of the Easyshade Advance device.

The Implementation of Elaborative Feedback for Qualitative Improvement of Shade Matching-A Randomized Study.

OBJECTIVES: The objective of this prospective learning research study is to examine the impact of structured elaborative feedback in practical skills teaching of visual and digital shade matching. MATERIALS AND METHODS: A total of 60 preclinical dental students participated in the study. The mean average age was 23 years, of which 37 were female (61.7%) and 23 male (38.3%). The participants were randomly divided into a study and control group (n = 30 each). Recording of shade matching was carried out on the phantom patient using clinically simulated settings with elaborative feedback in the study group (T1). Nine items were recorded for visual shade matching and six items for digital shade-taking. The errors were coded. The lower the total (max. 30 points), the fewer the errors made by students during shade determination. The subject labeled the tooth color using VITA 3D-Master and VITA Easyshade (Vita Zahnfabrik, Bad Säckingen, Germany). RESULTS: On comparing the two groups, the study group and the control group showed a similar mean error value at reference time T1. After intervention (T2) it was possible to achieve a clear improvement in the rate of errors for study group. In the study group there was a significant difference between the ΔE values from time T1 and T2 of visual shade matching (p <0.05). The digital ΔE values show in total no significant changes. CONCLUSION: Elaborative feedback in conjunction with standardized checklists can lead to a substantial improvement among students in terms of visual shade matching. CLINICAL SIGNIFICANCE: Correctly determining the tooth shade is an essential treatment step in esthetic reconstructive dentistry. Color is probably one of the most important determinants of esthetics in dentistry. Factors such as lighting conditions, gender, age, experience, and color vision impairment affect the process of shade matching. With an elaborative feedback in conjunction with standardized checklists can lead to a substantial improvement among students in terms of visual shade matching. (J Esthet Restor Dent 28:277-286, 2016).

The repeatability of digital shade measurement--a clinical study.

OBJECTIVES: The intraoral VITA Easyshade spectrophotometer is a shade measurement system that provides for objective determination of the shade of natural teeth and of dental materials. Over a period of 2.5 years, this clinical study assessed the repeatability of VITA Easyshade measurement, using metal ceramic restorations and based on L*a*b* parameters. MATERIALS AND METHODS: Shade tests of 25 metal ceramic crowns were carried out objectively in 19 patients using VITA Easyshade and subjectively by a dentist. The measurements were taken using a separate positioning device at the time of insertion, after 14 days (baseline), after 6 months, after 1.5 years and after 2.5 years. RESULTS: ∆E was calculated from ∆L*, ∆a*, ∆b* data as a measure of the differences in shade. The average values during the follow-up controls were ∆E 2 = 2.2 (6 months), ∆E 3 = 2.3 (1.5 years) and ∆E 4 = 2.0 (2.5 years). Subjective shade analysis during the follow-up controls did not reveal any changes in the ceramic veneer. CONCLUSIONS: The average of ∆E = 2.1 represented the difference in color. The examiner could not detect any difference in color over the evaluation period of 2.5 years. CLINICAL RELEVANCE: Good results in terms of the repeatability and accuracy of VITA Easyshade measurements were reported in previous in vitro studies. Objective assessment under clinical conditions is required in order to evaluate the shade stability of tooth-colored restorative materials in the oral cavity. For this purpose, the quality and handling of VITA Easyshade must be verified from a clinical perspective.

Potential Co-Factors of an Intraoral Contact Allergy-A Cross-Sectional Study.

The aim of this cross-sectional study was to evaluate the frequency of dental allergens and potential co-factors, especially hypothyroidism, for patients with an intraoral contact allergy. From 2015 to 2016, patients with confirmed symptoms of an intraoral contact allergy (study group SG n = 50) were recruited in the dental clinic of the University of Leipzig. The participants of the control group (CG n = 103) were patients without oral diseases or intraoral symptoms of a contact allergy. For the data collection, a new "Allergy questionnaire" was developed. Information on allergies and general diseases were collected. The statistical analysis was carried out with SPSS 23.0. Sensitizations/allergies to metals and composites were higher in SG compared to CG. Of all study participants (n = 148), 14.2% (n = 21) had a nickel allergy. In 18% (n = 8) of the SG a cobalt allergy based on all metal allergens could be seen. In addition, an association between a nickel and cobalt allergy was found. Hypothyroidism occurred significantly more frequently (p = 0.049) in SG than in CG. Sensitizations and allergies can occur to metals in dental alloys. Hypothyroidism increased the risk of having an allergy threefold.

Contact allergies to dental materials

There is a lack of epidemiological data on allergies to dental materials. For example, in the recently published fifth German Oral Health Study (DMS V), no information was given on any common allergies or allergies to dental materials. The aim of the present observational study was therefore to determine the frequencies and symptoms of allergies to dental materials. A public consultation hour for allergies of the oral mucosa and material incompatibilities has been integrated in the Department of Dental Prosthodontics and Materials Science in Leipzig, where clinical patient data have systematically been collected since 2012. The objective mucosal findings and the patients' complaints are documented in detail in a specifically designed data sheet. This study included 86 subjects (83.7% women and 16.3% men) with oral symptoms of a contact allergy. The average age was 63 years (24­86). The most common allergies were to metals, of which nickel and cobalt were the most common allergens. Furthermore, many allergies were indicated to ingredients of cosmetics and composites. Allergies to components in methacrylate-containing denture resins came in at rank 5. 52.4% of the patients showed mucosal changes. Contact stomatitis (54.5%) and an oral lichenoid lesion (20.5%) were most frequently diagnosed. 86% of the patients reported subjective complaints. Pain and burning sensations in the mouth were mostly reported. Appropriate dental allergy history, clinical examination of the oral cavity for changes in the oral mucosa, analysis of specific dentures, and screening for psychogenic disorders are necessary to clarify the origin of these symptoms.

Shade Stability of Polymer-Infiltrated and Resin Nano Ceramics.

BACKGROUND: The esthetics plays an increasingly significant role in today's dentistry. OBJECTIVE: The objective was to investigate the shade stability of a polymer-infiltrated and a resin nano ceramic in comparison to a conventional feldspar ceramic and an acrylate polymer. METHODS: 20 specimens of each of the materials, CAD-Temp (CT), Mark II (M), VITA Enamic (VE) and Lava Ultimate (LU), were prepared using the standard method. These were divided into groups (n=5) and placed in the following stain solutions: Distilled water, coffee, Coca-Cola and red wine for 14 days. The shade of each specimen was measured before and after using a spectrophotometer (n=5). The data were analyzed using ANOVA and Tukey's test (p ≤ 0.05). RESULTS: The largest ΔE mean values were observed in CT by Coca-Cola (4.38 ± 0.41), in M by coffee (5.95 ± 0.62), in VE (6.02 ± 0.78) and LU (8.61 ± 0.30) by red wine. LU had the largest and strongest overall shade differences (total score: SSC=16.95) and CT the least (SSC=8.74). Overall shade differences of VE (SSC=12.03) and M (SSC=12.48) were statistically indistinguishable. After 14 days, only Coca-Cola caused clinically relevant shade differences in CT (ΔE > 2.7); this was also caused by coffee, Coca-Cola and red wine in M and coffee and red wine in VE and LU. CONCLUSION: On average, VE showed fewer shade differences than LU. After 14 days of immersion, shade differences which exceeded the clinical acceptance threshold of ΔE=2.7 were shown by CT in Coca-Cola, by M in coffee, Coca-Cola and red wine, and by VE and LU in coffee and red wine.

Biomechanical properties of polymer-infiltrated ceramic crowns on one-piece zirconia implants after long-term chewing simulation.

BACKGROUND: Implant and superstructure provide a complex system, which has to withstand oral conditions. Concerning the brittleness of many ceramics, fractures are a greatly feared issue. Therefore, polymer-infiltrated ceramic networks (PICNs) were developed. Because of its low Young's modulus and high elastic modulus, the PICN crown on a one-piece zirconia implant might absorb forces to prevent the system from fracturing in order to sustain oral forces. Recommendations for the material of superstructure on zirconia implants are lacking, and only one study investigates PICN crowns on these types of implants. Accordingly, this study aimed to examine PICN crowns on one-piece zirconia implants regarding bond strength and surface wear after long-term chewing simulation (CS). METHODS: Twenty-five hybrid ceramic crowns (Vita Enamic, Vita Zahnfabrik) were produced using computer-aided design/computer-aided manufacturing (CAD/CAM) technology and adhesively bonded (RelyX™ Ultimate, 3M ESPE) to zirconia implants. Twenty of the specimens underwent simultaneous mechanical loading and thermocycling simulating a 5-year clinical situation (SD Mechatronik GmbH). Wear depth and wear volume, based on X-ray micro-computed tomography volume scans (Skyscan 1172-100-50, Bruker) before and after CS, were evaluated. All crowns were removed from the implants using a universal testing machine (Z010, Zwick GmbH&Co.KG). Subsequently, luting agent was light microscopically localized (Stemi 2000-C, Zeiss). With a scanning electron microscope (SEM, Phenom™ G2 pro, Phenom World), the area of abrasion was assessed. RESULTS: 1. After CS, none of the tested crowns were fractured or loosened. 2. The maximum vertical wear after CS was M = 0.31 ± 0.04 mm (mean ± standard deviation), and the surface wear was M = 0.74 ± 0.23 mm3. 3. The pull-off tests revealed a 1.8 times higher bond strength of the control group compared to the experimental group (t(23) = 8.69, p < 0.001). 4. Luting agent was mostly located in the crowns, not on the implants. 5. The area of abrasion showed avulsion and a rough surface. CONCLUSIONS: PICN on one-piece zirconia implants showed high bond strength and high wear after CS.

Bacterial Colonization and Tissue Compatibility of Denture Base Resins.

Currently, there is minimal clinical data regarding biofilm composition on the surface of denture bases and the clinical tissue compatibility. Therefore, the aim of this experimental study was to compare the bacterial colonization and the tissue compatibility of a hypoallergenic polyamide with a frequently used PMMA resin tested intraorally in a randomized split-mouth design. Test specimens made of polyamide (n = 10) and PMMA (n = 10) were attached over a molar band appliance in oral cavity of 10 subjects. A cytological smear test was done from palatal mucosa at baseline and after four weeks. The monolayers were inspected for micronuclei. After four weeks in situ, the appliance was removed. The test specimens were immediately cultivated on non-selective and selective nutrient media. All growing colonies were identified using VITEK-MS. The anonymized results were analyzed descriptively. A total of 110 different bacterial species could be isolated, including putative pathogens. An average of 17.8 different bacterial species grew on the PMMA specimens, and 17.3 on the polyamide specimens. The highest number of different bacterial species was n = 24, found on a PMMA specimen. On the two specimens, a similar bacterial distribution was observed. Micronuclei, as a marker for genotoxic potential of dental materials, were not detected. This study indicates that the composition of bacterial biofilm developed on these resins after four weeks is not influenced by the type of resin itself. The two materials showed no cytological differences. This investigation suggests that polyamide and PMMA are suitable for clinical use as denture base material.

Clinical comparison of liquid-based and conventional cytology of oral brush biopsies: a randomized controlled trial.

BACKGROUND: Exfoliative cytology performed on oral brush samples can help dentists to decide, whether a given oral lesion is (pre-) malignant. The use of non-invasive brush biopsies as an auxiliary tool in the diagnosis of oral mucosal lesions has gained renewed interest since improvements in cytological techniques such as the development of adjuvant diagnostic tools and liquid-based cell preparation techniques. METHODS: The aim of this study was to compare the quality of two different preparation techniques (cell collectors): the conventional transfer procedure to glass slides and the so-called liquid-based cytology preparation method. Cell smears were collected from 10 orally healthy individuals (mean age: 24 years) from the palatine mucosa at two different times (baseline and 4 weeks later). Slides of both techniques were stained by Giemsa (n = 40) and May-Gruenwald Giemsa (n = 40). The statistical analysis was performed with Excel. RESULTS: On specimen analysis, the liquid-based cytology showed statistically significant improvement compared to conventional glass sides (p < 0.001). Thin layers, which were performed by liquid-based cytology showed significantly better results in the parameters (p < 0.001): uniform distribution, cellular overlapping, cellular disformation, mucus, microbial colonies and debris. The conventional glass slides approach showed more cell overlapping and contamination with extraneous material than thin layers, which were performed by Orcellex® Brush cell collectors. CONCLUSIONS: Both techniques are diagnostically reliable. The liquid-based method showed an overall improvement on sample preservation, specimen adequacy, visualization of cell morphology and reproducibility. Liquid-based cytology simplifies cell collection due to easier handling and less transfer errors by dentists.

Allergen-getriggerte lichenoide Mundschleimhautläsionen: Diagnose und Therapie anhand eines Fallbeispiels.

Allergen-triggered lichenoid oral mucosa lesions may occur both in oral lichen planus (OLP) and oral lichenoid lesions (OLL). Clinically, OLP and OLL are difficult to distinguish from each other. An OLP should be checked by histological examination. Therefore all patients with OLP should be included into a close control interval due to the the potential malignant transformation, whereas in the literature a higher risk of malignancy is attributed to OLL in comparison with OLP. Based on a clinical case, it is demonstrated that an interdisciplinary approach in allergy and mucous diagnosis is necessary to verify the correaltion between a contact allergy to amalgam and the lichenoid mucosal lesions. The subsequent treatment exemplifies the steps of dental therapies with multiple contact allergies to dental materials.

Learning Shade Differentiation Using Toothguide Trainer and Toothguide Training Box: A Longitudinal Study with Dental Students.

The positive training effect achieved with the Toothguide Training Box (TTB) has been demonstrated in previous studies. The aim of this study was to investigate the training effect with the TTB at six and 12 months using standardized color tests. The study involved 101 dental students. The participants were divided into two study groups and one control group. Ten standard color samples were determined under uniform environmental conditions with VITA 3D-Master. The control group (N=30) took the color test after one week. Study group 1 (N=49) took the color test after six months and study group 2 (N=22) at 12 months for the first time by following the TTB curriculum. The control group achieved an average ΔEt1=0.85. In study group 1, the ΔEt2 was 2.29, and in study group 2, ΔEt3=2.25. The results after six and 12 months were highly significant compared to the control group (α=0.001). Dependence was determined only with regard to gender. In this study, the TTB quickly led to an improvement in tooth color differentiation among students. After six months, there was a decrease in the training effect. These results suggest that the TTB curriculum should be provided at the end of preclinical training.

Development and implementation of the Clinical Tooth Shade Differentiation Course--an evaluation over 3 years.

OBJECTIVE: Tooth shade differentiation concerns the identification and classification of tooth shades. The objective of this project was to implement the Clinical Tooth Shade Differentiation Course in the preclinical stage of studies and to evaluate the students' perspective over a period of 3 years. METHODOLOGY: The course is planned for a duration of 10 weeks with two 45-minute sessions per semester week. The entire attendance time was 10:15 h. 2 lectures of 90 minutes each, 2 seminars of 60 min each and 2 teaching units with the phantom head and role playing took place. In addition to the various parameters of tooth shade, changes in tooth shade and the basics of dental esthetics, clinical procedures for manual and digital tooth shade determination were explained and practiced. 96% (69 of 72) of the students participated in the first evaluation in 2012/2013 (T1), and 68% of these were women. In the following year, 2013/2014 (T2), 92% (45 of 48 students) took part; 62% of these were women and 38% men. The 2014/2015 evaluation (T3) comprised 94% (45 of 48 students). Of these, 67% were women. RESULTS: In the evaluation, the students gave the course a positive grade. The questions in "General/Organization" were given a mean (M) of 1.5 (SD=0.7) in T1 and T2, and 1.2 (SD=0.3) in T3. The "Overall Assessment" yielded M(T1)=1.6 (SD=0.6), M(T2)=1.5 (SD=0.5) and M(T3)=1.1 (SD=0.3). In T1 and T2, the item "The instructor actively involved the students in the course" was given a mean of 2.1 (SD=0.9), and in T3 a mean of 1.2 (SD=0.5). CONCLUSIONS: The course presented here conceptually shows how practical dental skills can be taught in a theoretical and clinical context. Educational objectives from the role of a dental expert were taken from the national competence-based catalog of educational objectives for dentistry and can also be supplemented. The objectives can be transferred to other dental faculties.