International Journal of Esthetic Dentistry (EN), 01/2011

A thorough understanding of the histoanatomic structures and dynamic light interaction of the natural dentition provides dental practitioners with the ultimate strategic advantage with regard to optical integration of the final restoration. The first part of this article will attempt to provide insight on the threedimensional coronal configuration of natural teeth and on the utilization of this knowledge in the clinical and technical restorative approach. The main goals for this article are to identify and reveal previously unreported histo-anatomic interrelationships and to explain existing ones: the sigmoid curve distribution (convex enamel/concave dentin), the distinction between dentinoenamel "junction" (DEJ, visual interface) and dentinoenamel "complex" (DEC, functional interphase), and the structural significance of DEC preservation.

Tooth wear represents a frequent pathology with multifactorial origins. Behavioral changes, unbalanced diet, various medical conditions and medications inducing acid regurgitation or influencing saliva composition and flow rate, trigger tooth erosion. Awake and sleep bruxism, which are widespread nowadays with functional disorders, induce attrition. It has become increasingly important to diagnose early signs of tooth wear so that proper preventive, and if needed, restorative measures are taken. Such disorders have biological, functional, and also esthetic consequences. Following a comprehensive clinical evaluation, treatment objectives, such as a proper occlusal and anatomical scheme as well as a pleasing smile line, are usually set on models with an anterior teeth full-mouth waxup, depending on the severity of tissue loss. Based on the new vertical dimension of occlusion (VDO), combinations of direct and indirect restorations can then help to reestablish anatomy and function. The use of adhesive techniques and resin composites has demonstrated its potential, in particular for the treatment of moderate tooth wear. Part I of this article reviews recent knowledge and clinical concepts dealing with the various forms of early restorative interventions and their potential to restrict ongoing tissue destruction.

The objective of dental treatment is the elimination of the etiologic factors, the rehabilitation of function and esthetics, and, when possible, the maintenance of vitality and structure of the natural dentition. After the loss of the periodontal support, as a consequence of periodontal disease, it may be necessary to splint the residual teeth in order to improve their stability, and sometimes it is also necessary to modify the morphology to optimize the final esthetic outcome. In many periodontally treated teeth, prosthodontic treatment on the residual dentition will be required with an important loss of tooth structure as an unavoidable consequence. This procedure frequently requires endodontic treatment of the residual abutments in order to obtain the necessary space for replacement materials. Similar objectives could however be achieved through an alternative therapy where the esthetic remodeling of the teeth and the closure of the interproximal spaces is obtained with composite resin materials. The objective of this article is to present an alternative protocol to optimize the functional and esthetic result of periodontally treated cases, where the most frequent complication is the increased length of the clinical crown. This is obtained by utilizing a different conservative approach, which has as its main objective the stabilization of the residual teeth, the maintenance of their vitality, and the achievement of the best esthetic result possible.

The clinical case presented is the demonstration of a multidisciplinary approach to a complex treatment. A precise methodology is important to ensure that the treatment objectives are clear to all the teams. The aim of the treatment is to restore dentofacial harmony to a young, 22-year-old, female patient showing severe attrition of the anterior teeth. The direct effect of this is an ageing of the smile. This type of multidisciplinary treatment, which seems complicated at first, is greatly simplified once time has been spent on the diagnosis and treatment plan: it thereby becomes a succession of clinical stages.

The most common esthetic challenge associated with endodontics is the discoloration of natural tooth structure. Also in fixed prosthesis, discolorations represent an esthetic limit, particularly in the case of all-ceramic restorations. In fact, the final esthetic result can be compromised by the grey radiated through the coping and soft tissue. Purpose: The aim of the study was to evaluate the masking ability of Procera alumina restorations. Materials and methods: Clinical evaluation was investigated by using tests of discolored teeth. Each abutment, classified with Natural Die Material (Ivoclar Vivadent), were manufactured three alumina copings with thickness of 0.4, 0.6, and 0.8 mm, respectively. Masking ability for each coping was evaluated in relation to the degree of discoloration. On the basis of the results obtained, seventeen discolored teeth, treated with Procera alumina restorations, were evaluated. Color match, porcelain surface, marginal discoloration, and marginal integrity were clinically examined following modified CDA/Ryge criteria. Conclusion: The Procera AllCeram alumina system seems to be a reliable and excellent technology for the prosthetic treatment of moderate and serious discolored anterior teeth with an exceptionally natural look.

This study examined the distances between the facial and palatal papillae (DFPP) in the maxillary anterior dentition. A total of 360 filled interdental papillae in 72 study models were examined (Group A: 36 young patients, Group B: 36 adult patients). The DFPP was measured directly on alginate impressions. In Group A, the average DFPP was 1.27 ± 0.6, 1.53 ± 0.42, and 1.83 ± 0.56 mm between the central incisors (CI-CI), central and lateral incisors (CI-LI), and lateral incisor and canine (LI-CA), respectively. In Group B, the respective average DFPPs were 1.3 ± 0.83, 1.38 ± 0.68, and 1.62 ± 0.58 mm. Within the limits of the present study, the average distances between the facial and palatal papillae seem to be useful for setting the proximal contact position.

Purpose: To determine the color space and the coverage error of two manual shade guide systems in four age groups of a selected population. Material and methods: A total of 174 patients were divided into four age groups and the shade of their natural teeth was measured (2067 teeth) with a spectrophotometer (Vita Easyshade). Color parameters in terms of L*, a*, b* values, chroma, and hue were recorded for each tooth. Color difference (ΔE*min) between each natural tooth and the closest match using two manual shade guide systems were calculated (3D Master shade guide standard and 3D Master shade guide with intermediate values). A Wilcoxon test was used to assess statistical differences between mean ΔE*min values for each system (α = 0.05). Results: The recoded ΔE of the two tested manual systems was 6.19 for 3D Master shade guide (standard) and 6.02 for 3D Master shade guide (intermediate values). A statistically significant difference (P < 0.001) was found between the mean ΔE*min of the two systems. 47% of natural teeth presented a best match with intermediate value and chroma shade tabs. The mean ΔE*min was influenced by the age group of the patients (5.15, 5.23, 6.58, and 6.69, respectively). Conclusion: Using intermediate value and chroma did not improve shade match, nor the coverage error of the tested population. Nevertheless, better coverage error was observed in younger age groups compared to older anterior teeth.