Anterior aesthetic restoration with ultrathin porcelain veneers on asymmetric faces assisted by a four-dimensional smile design: a case report and literature review / 口腔疾病防治

Objective@#To explore the application effect of a four-dimensional smile design as the leading and facial streamline as the reference system in the aesthetic restoration of anterior teeth.@*Methods@# A case of scattered space in anterior teeth was treated with a four-dimensional smile design and digital aesthetic restoration with ultrathin porcelain veneer. The digital information of the patients was obtained through oral and facial scanning, and a four-dimensional smile design and prediction were carried out. After the treatment plan was jointly determined by doctors and patients, minimally invasive abutment preparation was carried out, and ultrathin porcelain veneer was made and bonded in place. After the operation, the esthetic degree and marginal fit were observed and reexamined one year after the repair.@* Results @#The edges of the ultrathin ceramic veneers were naturally tight, and the color was coordinated, with satisfying pink and white esthetics. The face was more harmonious and natural when smiling. One year after the restoration, the facial aesthetics were wonderful, the abutment teeth and periodontal tissues were healthy, and the patients were satisfied. The results of the literature review showed that the fitting of temporal facial scanning and intraoral scanning data can accurately predict four-dimensional smile aesthetics, simulate the real state of the dynamic smile and pronunciation process, and combine it with facial streamlines to design a natural and coordinated personalized smile for patients with asymmetric faces. However, for patients with occlusal changes, unstable occlusion or temporomandibular joint disorder, it is necessary to add data fitting, such as electronic facial arch and cone beam CT, to more accurately simulate postoperative mandibular movement.@*Conclusion@# With a four-dimensional smile design as the leading and facial streamline as the reference system, the whole process digital design assisted the restoration of asymmetric anterior teeth with ultrathin porcelain veneer and had a good effect. The postoperative smiling of patients is harmonious and beautiful, which is in line with the expected effect. Patient participation and satisfaction are high; thus, this method is worthy of clinical promotion.

A randomized controlled study on color stability of tetracycline teeth restored with ceramic veneer / 华西口腔医学杂志

OBJECTIVES@#This study aimed to evaluate the color stability of tetracycline teeth restored with ceramic veneers of different thicknesses combined with different resin cement systems after aging.@*METHODS@#Twenty patients with tetracycline teeth, including two maxillary central incisors, were selected clinically. The patients were randomly divided into four groups and restored with 0.5 and 0.75 mm ceramic veneers by using a veneer adhesive system, either with light-cured or dual-cured reaction. The color difference (ΔE) values after cementation and 1, 6, 12, and 24 months of use were obtained by quantification of L*, a*, and b* values with a colorimeter. The results were analyzed statistically with two-way ANOVA and Student's @*RESULTS@#The ΔE values of ceramic veneers detected after aging were less than 2.25. The 0.5 mm groups exhibited greater color change than the 0.75 mm-thick veneers (@*CONCLUSIONS@#Resin cements and veneer thickness influence the color of ceramic veneers after aging. Cementation of veneers with either dual- or light-cured resin cements does not affect the long-term color stability of tetracycline teeth differently.

Interdisciplinary planning as a landmark for treatment: Case report with a 2-years follow-up

Abstract Case report: young adult woman with esthetic complaints regarding her smile and frontal teeth aspect. At first glance, the problem seemed to be only the shape of the lateral upper incisors and a small diastema between the central incisors. The diagnosis shared between the orthodontist and the prosthetist led us to consider some other important aspects, such as the deep bite, the teeth inclination and the lips support. All these findings led us to consider that the right way to improve the esthetics of the patient's smile was to plan an orthodontic treatment. This would serve not only for the distribution of the spaces, but mostly it would improve all other problems, before the restoration of the upper lateral teeth with two ceramic veneers. Results: the treatment plan achieved the right distribution of spaces for upper lateral incisors, significant correction of the incisors inclination with important reduction of overbite and better lip support, upper laterals restorations with ceramic feldspathic veneers, obtaining a good integration with natural teeth satisfying patient complaint. Conclusion: in cases which involve interdisciplinary approach, the fundamental step comes from the beginning, when only an initial diagnosis shared among the team of specialists can define the patient problems from different points of view. In this way, we can better understand the competency fields and plan the right treatment and time sequence.

Resumo Relato de caso: paciente adulta jovem, sexo feminino, buscou tratamento devido à queixa com a estética do sorriso e o aspecto dos dentes anteriores. À primeira vista, o problema parecia ser apenas o formato dos incisivos laterais superiores e um pequeno diastema entre os incisivos centrais. O diagnóstico conjunto do ortodontista e do protesista fez com que considerássemos outros aspectos importantes, tais como mordida profunda, inclinação dentária e suporte labial. A partir de todas essas constatações, consideramos que a maneira mais adequada de melhorar a estética do sorriso seria planejar o tratamento ortodôntico. Assim, o tratamento serviria não apenas para melhor distribuição dos espaços, mas também melhoraria todos os outros problemas antes da restauração dos dentes laterais superiores ser realizada com duas facetas de cerâmica. Resultados: o tratamento planejado levou à correta distribuição dos espaços nos incisivos laterais superiores, com correção significativa da inclinação dos incisivos, importante redução da sobremordida e um melhor suporte labial, com restauração dos laterais superiores usando facetas de cerâmica feldspática, obtendo-se uma integração ideal com os dentes naturais, resolvendo as reclamações da paciente. Conclusão: em casos envolvendo abordagem multidisciplinar, as etapas iniciais são fundamentais, e apenas um diagnóstico inicial discutido entre a equipe de especialistas pode determinar os problemas do paciente sob diferentes perspectivas. Dessa forma, podemos compreender melhor os campos de competência e planejar a sequência e o tempo de tratamento mais adequados.

Evaluation of marginal discrepancy of pressable ceramic veneer fabricated using CAD/CAM system: Additive and subtractive manufacturing

PURPOSE: The purpose of this study was to evaluate the marginal discrepancy of heat-pressed ceramic veneers manufactured using a CAD/CAM system. MATERIALS AND METHODS: The ceramic veneers for the abutment of a maxillary left central incisor were designed using a CAD/CAM software program. Ten veneers using a micro-stereolithography apparatus (AM group), ten veneers using a five-axis milling machine (SM group), and ten veneers using a traditional free-hand wax technique (TW group) were prepared according to the respective manufacturing method. The ceramic veneers were also fabricated using a heat-press technique, and a silicone replica was used to measure their marginal discrepancy. The marginal discrepancies were measured using a digital microscope (×160 magnification). The data were analyzed using a nonparametric Kruskal-Wallis H test. Finally, post-hoc comparisons were conducted using Bonferroni-corrected Mann-Whitney U tests (α=.05). RESULTS: The mean±SD of the total marginal discrepancy was 99.68±28.01 µm for the AM group, 76.60±28.76 µm for the SM group, and 83.08±39.74 µm for the TW group. There were significant differences in the total marginal discrepancies of the ceramic veneers (P < .05). CONCLUSION: The SM group showed a better fit than the AM and TW groups. However, all values were within the clinical tolerance. Therefore, CAD/CAM manufacturing methods can replace the traditional free-hand wax technique.

Color and opacity variations of veneer after bonding by resin cements and accelerated aging / 实用口腔医学杂志

Objective:To assess the effect of accelerated aging on the color and opacity of veneers bonded resin.Methods:28 discs were made with IPS e.max Press A1 shade with the thickness of 0.4 mm.Ceramic discs were divided into 4 groups(n=7). BEAUTIFIL Flow A1 ,DEO-Link SE Transparent,Panavia F Light color and Viriolink N transparent resin cements were applied on the porcelain discs with a thickness of 0.1 mm.Curing was performed with a calibrated LED curing-light for 40 seconds.Color and opac-ity differences of the porcelain substructures after 65 h(150 kJ/m2 )of UV ageing test were examined with a colorimeter.The results were analysed statistically with One-way ANOVA,LSD(L)test.Results:All samples showed significant changes in color and opaci-ty.The ΔE of all materials ranged from 0.6 to 2.29.DEO-Link SE showed the highest color change,while BEAUTIFIL Flow the lowest.The opacity changes ranged from 0.46 to 2.55 and its variation was not significant among groups except for Panavia F.Con-clusion:The accelerated ageing may lead to color changes of ceramic veneer bonded by resins in a clinically acceptable range(ΔE<3).

Aesthetic restoration of full ceramic veneer by slip casting / 实用口腔医学杂志

Full ceramic prosthesis is becoming the main prosthetic development direction. As an important kind of full ceramic prosthesis, full ceramic veneer has not only natural cosmetic appearance and perfect biocompatibility, but also can preserve tooth structure as much as possible, which would be more easily accepted by patients for cosmetic prosthesis. Many methods, such as slip casting, die casting and CAD/CAM technology are available to make full ceramic veneer. All the methods have their own advantages and disadvantages. Slip casting is easy to be developed widely with low cost, so be used in practical work. In this article, the working process of full ceramic veneer, especially manufacture of removable dies, duplication of refractory models, were introduced, which was supposed to be beneficial for the technicians.

The evaluation of the masking ability of the Rely X~(TM) Veneer try-in pastes / 实用口腔医学杂志

Objective:To evaluate the masking ability of the Rely XTM Veneer try-in pastes. Methods: 100 discolored teeth, including 50 nonvital ones and 50 vital ones, has been collected and restored respectively with all-ceramic crowns and veneers. Five try-in pastes including A1, A3, Translucent (Trt), White opaque(WOT) and B0.5 Opaque(B0.5),which were different in shade, were used to try in before adhesion. The color was measured by a digital colorimeter, and expressed in terms of 3 coordinate values(L*、a*、b*) of the CIE1976- L*a*b* system.Then the color differences of crowns and veneers ?E=[(?L*)2+(?a*)2+(?b*)2]1/2 as well as the value of Light (L= L*)、Chroma[C=〔(a*)2+(b*)2〕1/2] and Hue [H=arctan(b*/a*)] were calculated. The thickness of the measurement point was also measured and recorded. A one-way ANOVA was used to analyze ?E as well as L, C and H. Results:The chromatism of the veneers after try-in was higher than that of the crowns(P

Two dimensional finite element analysis of ceramic veneer bonding layer / 实用口腔医学杂志

Objective: To intimately assess the internal stress distribution in ceramic veneer bonding layer. Methods:Six buccolingual cross section models of the incisor restored with IPS-Empress ceramic veneer were built with the MSC/NASTRAN software. 2D-finite element method was used to analyze the stress distribution regularity of the bonding layer on the models under different functional load. Results: Stress concentration areas of ceramic veneer bonding layer were regularly located on the incisal margin and cervical margin. Under the same condition, incisal load caused highest stresse on the adhesive layer. Following the load shift from incisal to gingival area, the stress was gradually decreased.When the functional load acted on the palate margin of the restoration, the compressive stress on the bonding layer was significantly increased. Different load angle generated stress change in the bonding layer. The shear stress on adhesive layer increased following the horizontal load angle increasing close to the debonding level. Among the different incisal reduction designs there was no significant Von Mises stress variation under the same load condition. However, when the incisal edge was reduced by more than 4 mm, the tensile stresses in the bonding layer greatly increased. Conclusion: Restoration margin should be kept away from the tooth contact area, be exposed to minimal occlusion contact. The functional load should be induced to follow the tooth long axis. Edge to edge occlusion should be avoided. When incisal areas need to be altered, the incisal overlap or butt margin design will not cause any stress problem in the bonding layer. When restoring the incisal defect for more than 4 mm, the bonding agents must be selected carefully.

EVALUATION OF COLOR OF THINNER CERAMIC VENEER RESTORATION / 解放军医学杂志

This study was to evaluate the clinical application of thinner ceramic veneer restoration. Tooth color was measured by eye and colorimeter after thinner ceramic veneer restoration. The results showed that there were many factors influencing the color of its clinical restoration. Hue of the ceramic veneer, ceramic materials and bond composites had greater influence than that of dentition. The brightness of ceramic materials and bond composites was closely correlated with the whole restoration brightness. A closer correlation was found with the brightness of bond composite. Thinner ceramic veneer restoration can achive satisfactory results.