International Journal of Esthetic Dentistry (EN), 03/2012

In this article, the interdisciplinary management of an isolated-type recession defect in a severely compromised mandibular incisor of a young post-orthodontic patient is described. The prognosis of root coverage surgery was very questionable and unpredictable due to the severe root malposition (III Miller class gingival recession). The treatment plan consisted of: (1) interproximal enamel reduction to gain space within the dental arch, (2) orthodontic repositioning of the root of the affected tooth within the alveolar bone and (3) root coverage mucogingival surgery. Clinical re-evaluation 7 months after fixed orthodontic treatment revealed major improvements in the root coverage prognosis due to the resolution of root malposition and de novo formation of keratinized tissue apical to the root exposure (I Miller class gingival recession). A subepithelial connective tissue graft was performed as a root coverage surgical procedure. Clinical examination 1 year after surgery revealed complete root coverage, good color blending with adjacent soft tissue and an increase in facial gingival thickness. Successful periodontal and esthetic outcomes can be accomplished after the combined orthodontic-periodontal treatment of a severely mucogingivally compromised tooth.

Porcelain laminate veneer restorations are much thinner than other types of restorations such as crowns or onlays. Within the range of 0.3 to 1.5 mm, it is not an easy task for the clinician to provide the appropriate clearance for the ideal restoration and, concurrently, for the dental technician to predictably create a piece of imitated nature. The advantages of enamel preservation and the principle of nil nocere imply removing as little tooth structure as possible for the purpose of maintaining tooth health, its mechanical strength and ensure the treatment's long-term predictability. There has to be a balance between the requirements of reduction clearance, which will enable the technician to achieve the desired esthetic result, and the minimally invasive principles of dentistry. With laminate veneer cases, there might be areas of variable ceramic thickness that can create esthetic problems. These will be hard to correct during cementation and will also be clearly visible to the patient. Clinical cases are presented here to outline this type of problem.

Purpose: The presence of a treatable gingival recession in teeth ready for crown preparation requires a combined restorative-periodontal effort to achieve all biologic and esthetic goals. This needs an ideal artificial crown proportion and a harmonious gingival architecture. Traditionally, a root coverage procedure is initially performed followed by final crown preparation and cementation. However, during the prosthetic phase, irritation to the grafted delicate tissue may be followed by recession and exposed crown margins. To minimize prosthetic irritations, the "crown-then-graft approach" (CTGA) is suggested in which the root coverage procedure is performed after final crown preparation. Methods: After definitive crown preparation and impression taking of the left maxillary incisor, an acrylic crown with flat marginal profiles was temporarily cemented into the patient's mouth. Root coverage procedures were implemented using a combined connective tissue graft and a coronally advanced flap. No additional tooth preparation and impression taking were performed. After 6 months, a final crown, fabricated from the previous impressions, was cemented. Results: Initially, the grafted tissue margins completely covered the root and 1-2 mm of the temporary crown margins. At 12 months post-surgery and 6 months post-definitive crown cementation, the gingival margins slowly receded, reaching the ideal position. Complete root coverage was maintained for the next 5 years. Conclusions: The CTGA may minimize tissue irritation after root coverage in teeth designed for combined crown preparation and root coverage procedure, and may account for long-term marginal tissue stabilization.

Rehabilitation of edentulous spaces in esthetic areas is a challenge to the clinician due to the loss of soft tissues. In these clinical situations, it would be desirable to evaluate and predict the gingival architecture to recover in the oral rehabilitation. To fulfill this need, the diagnostic wax should anticipate the final rehabilitation with the integration of hard and soft tissue. Thus, it is essential to produce a diagnostic waxup that integrates these two components that are simultaneously seeking to recreate the harmony of white and pink esthetic. This diagnostic waxup will be the basis for the creation of the provisional prosthesis and a soft tissue mock-up. After placing the provisional prosthesis in the mouth, the soft tissue mock-up can be applied to assess its esthetic impact at facial and intraoral level. Dentist and patient should objectively assess the appearance of the final result. After approval of this rehabilitation concept, the virtual surgical planning can be performed and the surgical guide can be designed, allowing the treatment to take place. This protocol allows the development of a rigorous treatment plan based on the integration of teeth and gingiva component. The waxup and the soft tissue mock-up play a significant role, since they allow an earlier evaluation of the esthetic result, better prosthetic and surgical planning, and it allows us to anticipate the need for gingiva-colored ceramics use. The authors present a clinical case report of the importance of the wax-up and soft tissue mock-up in the treatment plan.

Objectives: This in vitro study evaluated the accordance of dental color measurement devices with a Commission Internationale de l'Eclairage (CIE)-compliant reference system, by comparing the CIE lightness, chroma, and hue (L*C*h°) color coordinates of ceramic samples. Methods: Four color measurement devices: Vita Easyshade® Advance (A); DeguDent Shadepilot™ (B); X-Rite® Shadevision™ (C); and Crystaleye Olympus (D), were compared with a CIE-compliant reference system by recording the L*C*h° color coordinates of ceramic samples matching the tooth colors of the Vita Linearguide 3D-Master®, under standardized test conditions. Differences between regression lines for the dental color measurement device data and regression lines for the CIE-compliant reference system data were evaluated. Results: All devices offered high intraclass correlation coefficients (0.9771- 0.9999) for the L*C*h° color coordinates. The regression lines of the L* and C* coordinates for device A were steeper than those of the CIE-compliant reference system; the regression lines for devices B, C, and D were nearly parallel to those of the reference system, but with an offset. The regression lines of the h° coordinates for all devices were almost parallel to those of the reference system, with slopes near 1. Excluding the L* and h° coordinate measurements of device A, the measurements with the devices exhibited deviations from the reference system that were greater than those expected by chance (P 0.0002). Conclusions: The dental color measurement devices assessed here offered excellent reproducibility, but showed significant deviations from the CIE-compliant reference system regarding the L*C*h° color coordinates.

This study examined the correlation between maxillary anterior tooth form and gender with three-dimensional data. Three-dimensional digital models of the area between the maxillary right central incisor and the maxillary right canine were obtained from 120 Caucasian subjects (60 males and 60 females) with healthy dentitions. Correlation between gender and tooth form was assessed applying logistic regression, with and without size standardization. Success rates were estimated using 10-fold cross-validation. Principal components that correlated with gender were evaluated with a Wald test. Values for the significance of the predictors were provided with a likelihood ratio test (P 0.05). Significant correlation between gender and tooth shape was found for the maxillary central incisor (P = 0.003), lateral incisor (P = 0.001), and canine individually (P = 0.001), and for the three teeth combined (P = 0.001) without size standardization. For the maxillary right lateral incisor (P = 0.004), canine (P = 0.001), and the combination of the teeth (P = 0.001), a correlation was also established after size standardization. Prediction of gender was not possible without information on tooth size for the maxillary right central incisor (P = 0.15). Maxillary anterior teeth have gender-specific differences. Differences in tooth size account for part of the correlation. However, tooth shapes are also gender specific.

The objective of this in vitro study was to evaluate the kinetics of hydrogen peroxide (HP) release from five different bleaching products: VivaStyle® 10% fitted tray gel, VivaStyle® 30% in-office bleaching gel, VivaStyle® Paint-On Plus paint-on bleaching varnish, Opalescence PF® 10% carbamide peroxide gel and Trèswhite Supreme™ 10% HP gel. Each product was firstly titrated for its HP content by a described method. HP release kinetics was assessed by a modified spectrophotometric technique. One sample t test was performed to test for differences between the manufacturers' claimed HP concentrations and the titrated HP content in the whitening products. Analysis of variance plus Tamhane's post hoc tests and Pearson correlation analysis were used as appropriate. Values of P 0.05 were taken as significant. Titrated HP revealed an increased content when compared to the manufacturer's specifications for all the products tested (P 0.05), although only products from one manufacturer produced significantly higher results. All products presented a significant (P 0.05) and sustained release of HP. However, the product with paint-on cellulose-based matrix resulted in significantly (P 0.05) faster kinetics when compared to other products tested. These results are consistent with manufacturers' reduced recommended application times. The results of this study suggest that modifying the matrix composition may be a viable alternative to HP concentration increase, since this may result in faster release kinetics without exposure to high HP concentrations. Keywords: dental whitening, hydrogen peroxide release, in vitro, kinetics