International Journal of Esthetic Dentistry (EN), 02/2010

Enhancement of facial beauty is one of the primary elective goals of patients seeking dental care. Frequently, improvements in natural beauty can be expected to follow restoration of ideal relationships between the denture and the facial soft tissues. A very important feature in a youthful appearance is the incisal tooth display; the amount of maxillary incisal exposure gradually decreases with age, accompanied by a gradual increase in mandibular incisal exposure. However, this problem could be present in young people where the effects of age should not be apparent yet. There are some other factors that could accelerate this process. The present case illustrates the improvement and rejuvenation of an unesthetic young smile through restorative treatment.

The use of small-diameter implants is indicated when small missing teeth have to be replaced, especially in esthetic zones. Nevertheless, the small diameter can pose a limiting factor with respect to what materials can be used for the final crown. In most cases, full-ceramic crowns in combination with a ceramic abutment are usually the material of choice for final reconstructions. To date, based on mechanical considerations, a 3.5 mm implant diameter has been a contraindication for using ceramic abutments. The authors describe here the development, in vitro testing, and clinical use of a zirconium abutment with a 3.5 mm diameter. The advantages of this small-diameter zirconia abutment include a minimum platform height that offers optimal prosthetic flexibility, and an accurate transfer of the implant position on to the master model. Furthermore, a precise rotational orientation for single-tooth restorations, optimal mechanical stability, and optimal fatigue resistance can be achieved. The microgap is minimized and protection against overload is afforded. In the reported case, high patient satisfaction was achieved due also to an esthetically pleasing final result.

Guided implant surgery is becoming a clinical reality in the world of implant dentistry. In recent years, a Computer Aided Implantology Academy has even appeared, confirming the importance of this approach. Different navigation systems are available for the planning of surgical and prosthetic reconstructions. These systems make available to the surgeon and the prosthodontist the instruments necessary to plan a case and to work in a team to deliver a fixed restoration at the time of the surgical procedure in a minimally invasive and predictable way. This article evaluates the usefulness of this kind of planning in the esthetic zone, where perfection is mandatory.

This case report describes the full-mouth oral rehabilitation of a titanium allergic patient. The patient was a young female with amelogenesis imperfecta who had generalized massive tooth destruction. All teeth in the mouth were extracted and 15 CeraRoot acid-etched (ICE surface®) implants were placed (seven implants in the maxilla and eight implants in the mandible). No immediate temporaries were placed. Temporaries were placed 3 months after surgery, and left in function for 2 months. The case was finally restored with zirconium oxide bridges and ceramic veneering (three bridges in the maxilla and another three in the mandible). The 3-year follow-up showed good stability of soft tissues and bone level. Zirconium oxide implants and restorations might be an alternative for the oral rehabilitation of titanium allergic patients.

It would be expedient to develop a simple digital procedure for matching shade guides to teeth for dental restorations. It was hypothesized that precise and objective L*a*b* measurements could be performed on photographic images of teeth and shade guides using commonly available photo software. Tooth shade guide tabs, shaped like computer-generated posterior crowns, were used for color matching. Digital photographs were obtained of the vestibular surface of the tooth and the neighboring shade guide. Sections of the tooth and shade guide on the photograph were cropped and analyzed in Photoshop CS2. The precision error of the measurements was expressed as the coefficient of variation in percent. The effects of tolerance setting and number of measurements and analysts were evaluated. The difference in color was calculated as the ΔE L*a*b*. The precision errors of the L*a*b* measurements with a tolerance setting of 6 pixels were better than 1.3%. There was no significant difference between one and five repeated measurements or between the measurements and the precision errors of two analysts. Color differences (ΔE) between repeated measurements were below 0.5 units, thus reproducible and visually identical. ΔE L*a*b* calculations were expedient for matching a particular color guide tab to the neighboring tooth. The color coordinates L*a*b* of teeth and shade guides can be calculated with a precision error of only 1.3%, using readily available software. A tolerance setting of 6 pixels is optimal and only one measurement and one analyst are necessary for objective and precise measurements. The described digital L*a*b* measurements on a photograph offer the dentist and the ceramist a simple, precise, and objective tool for matching tooth and shade guide.

The objective of the present study was to assess the clinical efficacy of a dental bleaching system based on hydrogen peroxide with or without light activation. This randomized controlled trial evaluated the effect of the light when applied to the hydrogen peroxide by using a split-mouth design with 21 patients, with light activation in one hemi-arch but not in the other. The bleaching agent was QuickWhite 35% hydrogen peroxide and activation was conducted with a diode lamp (Luma Cool®). The Classic Vita Guide was used to score tooth shades. Two consecutive applications of hydrogen peroxide were made to one hemi-arch, each light-activated for 10 min. The other hemi-arch was then identically treated but without light activation. After removal of the bleaching agent, the shade was re-scored and the Wilcoxon signed ranks test was used to compare differences in tooth shade values. The bleaching treatment produced significant shade changes (P < 0.01) in both hemi-arches. After treatment, there were no statistically significant differences between light-treated and non-lighttreated tooth types (central incisors, lateral incisors, and canines). However, taking central incisor, lateral incisor, and canine as a group, comparison between each hemi-arch showed a significant effect in the hemi-arch with light activation (P < 0.05). The use of diode light with a 35% hydrogen peroxide gel slightly improved the dental bleaching.