International Journal of Esthetic Dentistry (EN), 04/2010

Discolored dental substrates continue to challenge the restorative team when ultraconservative treatment modalities are chosen. An innovative laboratory concept - the parallel stratification masking technique - has been developed in order to achieve maximum preservation of dental hard tissues and predictably accomplish a desirable esthetic outcome. The major advantages of this technique are that the ceramist is able to: a) identify and map the discolored dental substrate, b) predictably mask the discolored dental substrate, and c) assess the appropriate masking efficacy of the fabricated restoration prior to laboratory delivery to the dentist in cases of bonded porcelain restorations.

Guided bone regeneration is a well- established technique used for augmentation of deficient alveolar ridges. There is much evidence in the literature to support the success of this procedure. Multiple techniques have been introduced using various types of membranes and bone grafting materials. However, efficacious regeneration requires both a high level of technical skills and a thorough understanding of major biological principles. This case report is presented to illustrate a reliable approach to successful management of two different alveolar defects.

Tooth extraction will be followed by marked alterations to the tissue volume, in particular in the anterior zone, which may jeopardize the esthetic outcome of any dental treatment involving tooth extraction. If, however, ridge collapse can be prevented or minimized after tooth extraction, more predictable outcomes with superior esthetics can be accomplished along with fewer surgical procedures. Therefore, it was proposed that stabilizing the soft tissue architecture with a free gingival graft could minimize the soft tissue shrinkage. The following case report describes some surgical modifications and refinements in order to enhance the predictability of the socket- seal surgery.

Introduction: An attractive smile helps people feel more self-confident and look younger. One of the more controversial aspects of smile attractiveness pertains to buccal corridor size. There is no previous study by those with artistic knowledge that has assessed the esthetic considerations of buccal corridor size. The purpose of this study was to observe whether the size of buccal corridors has an impact on smile attractiveness evaluated by lay people, dental students, and art students. Materials and Methods: Colored posttreatment photographs with posed smiles of two subjects (one male, one female) were selected. The maxillary posterior dentitions were digitally altered to produce different buccal corridor sizes: narrow (28% buccal corridor), mediumnarrow (22% buccal corridor), medium (15% buccal corridor), medium-broad (10% buccal corridor), and broad (2% buccal corridor). The 5 images of each subject were paired into 11 possible combinations and presented to three groups: art students, dental students, and lay people, who compared the two images in each pair for smile attractiveness. The statistical tests used were Wilcoxon signed rank test and Mann- Whitney test. Results: Minimal and excessive buccal corridors were the least attractive when judged by three groups. All groups preferred smaller buccal corridors for the male subject and larger buccal corridors for the female subject. No significant judging differences were found between male and female judges from among art and dental students. Conclusions: Minimal or excessive buccal corridors should be included in the problem list during orthodontic diagnosis and treatment planning.

The purpose of the present study was to evaluate enamel bond strength of a composite resin material after hydrogen peroxide bleaching, activated by a diode laser (LaserSmile), an ozone device (HealOzone), a light-emitting diode (BT Cool whitening system), and a quartztungsten- halogen device (Hilux Ultra Plus). Fifty extracted caries-free permanent incisors were used in this study. Thirty-eight percent hydrogen peroxide gel was applied to sound, flattened labial enamel surfaces and activated by different sources. Enamel surfaces that had received no treatment were used as control samples. Bonding agent was applied according to the manufacturer's instructions and the adhesion test was performed according to ISO/TS 11405. Statistical analysis showed significant influence of the different activation techniques of hydrogen peroxide on shear bond strength to enamel (ANOVA, LSD, P 0.05). The data in this in vitro explorative study suggest that activation of hydrogen peroxide by different sources may further affect the shear bond strength of subsequent composite resin restoration to enamel. Within the limitations of this in vitro study, further studies examining the structural changes of activated hydrogen peroxide-treated enamel are needed. Due to the different activation methods' duration of light irradiation, power densities, and dehydration effects, longer time periods may be needed before application of adhesive restorations to enamel, compared with non-activated bleaching.

Reattachment of the fractured fragment of a traumatized tooth (whenever available and usable) has become the treatment of choice in cases of uncomplicated crown fractures. Despite the presence of various bonding materials and techniques, laboratory data evaluating the biomechanical aspects of such procedures is largely lacking in the literature. The objective of this in vitro study was to evaluate the fracture strength recovery of incisors, following fragment restoration with three different esthetic bonding materials using three different techniques. A total of 90 extracted human maxillary central incisors were subjected to crown fracture under standard conditions. This was carried out by applying a compressive force from the buccal aspect of the clinical crown using a universal strength testing machine. The fractured teeth were equally distributed in three groups, defined on the basis of the technique used for reattachment: i) overcontour, ii) internal dentinal groove and iii) direct buildup. Each group was further subdivided into three subgroups on the basis of the intermediate restorative material used for reattachment, namely: i) hybrid composite (Filtek Z100 Universal Restorative), ii) nanocomposite (Filtek Z350) and iii) Ormocer (Voco Admira). Following reattachment, the crowns were re-fractured under standard conditions. The force required for fracture was recorded and was expressed as a percentage of the fracture strength of the intact tooth. The data was analyzed using two-way ANOVA and Bonferroni tests for pair-wise comparison. The results showed no statistically significant differences in fracture strength between the three groups (P >0.05). However, comparison of the subgroups revealed statistically significanty higher strength recovery percentages for the hybrid and the nanocomposite compared with the Ormocer material (P 0.05). It was concluded that material properties have a significant influence on the success of reattachment procedures.