International Journal of Esthetic Dentistry (EN), 02/2008

Apical surgery is often a last resort, and is used to surgically preserve a tooth with a recurrent lesion of endodontic origin when conventional re-treatment is neither indicated nor clinically or financially feasible. Incision type and flap design are important factors to consider when outlining the surgical area: the first must ensure optimal access to the root end and the second must allow visibility. A variety of factors must be considered when choosing a specific incision technique, particularly in the anterior maxilla. These include status of the marginal periodontium, location and extent of the periapical lesion, presence of a restoration margin, and the patient's esthetic demands. The outcome with respect to soft tissue healing following apical surgery will further depend on anatomical and surgical aspects, such as the biotype of the gingiva, maintenance of vascular supply, marginal bone structure, technique of flap elevation and retraction, duration of surgery, and wound closure. It is important to address soft tissue healing with the patient during planning of apical surgery because, in solving the endodontic problem, a gingival recession may have been created.

Traditionally, a full-mouth rehabilitation based on full-crown coverage has been recommended treatment for patients affected by severe dental erosion. Nowadays, thanks to improved adhesive techniques, the indications for crowns have decreased and a more conservative approach may be proposed. Even though adhesive treatments simplify both the clinical and laboratory procedures, restoring such patients still remains a challenge due to the great amount of tooth destruction. To facilitate the clinician's task during the planning and execution of a full-mouth adhesive rehabilitation, an innovative concept has been developed: the three-step technique. Three laboratory steps are alternated with three clinical steps, allowing the clinician and the laboratory technician to constantly interact to achieve the most predictable esthetic and functional outcome. During the first step, an esthetic evaluation is performed to establish the position of the plane of occlusion. In the second step, the patient's posterior quadrants are restored at an increased vertical dimension. Finally, the third step reestablishes the anterior guidance. Using the three-step technique, the clinician can transform a full-mouth rehabilitation into a rehabilitation for individual quadrants. The present article focuses on the second step, explaining all the laboratory and clinical steps necessary to restore the posterior quadrants with a defined occlusal scheme at an increased vertical dimension. A brief summary of the first step is also included.

The purpose of this study was to evaluate the efficacy of nonvital bleaching and clinical performance of direct composite restorations when used to reconstruct multisurface restorations on endodontically bleached teeth. Twenty-one patients 18 years or older were included in this clinical trial. Twenty-six endo-bleached maxillary and mandibular teeth were restored using a microhybrid composite resin. A Vita shade guide arranged by value order was used to record the shade for each patient. Temporary or existing restorations were removed along with 1mm of gutta-percha below the cementoenamel junction and a resin-modified glass ionomer barrier was placed. Bleaching treatment was performed in the office and at home. Two weeks after the completion of bleaching, teeth were restored using a combination of a filled adhesive system and microhybrid composite resin. All but one restoration was evaluated every 12 months during a 5-year period using modified United States Public Health Service criteria by two independent evaluators. No failures were reported and alpha scores were recorded for all parameters except color stability (Alpha: 10; Bravo: 14; Charlie: 1). ANOVA showed a significant shade change between baseline (mean = 14.13) and 2 weeks (mean = 1.6), 2 years (mean = 2.8), and 5 years (mean = 3.4), P < .0001. A post hoc test showed a significant shade change between a 2- week and 5-year follow up (P = .001). Shade rebound was reported for 15 out of 25 nonvital teeth, but was limited to a maximum of 6 shades; direct anterior composite restorations demonstrated outstanding clinical performance after 5 years.

The purpose of this study was to evaluate the influence of the core material (Spinell or Alumina) and the glass infiltration mode (under or without vacuum) on the color of 2M2 Vita In-Ceram Spinell and Alumina ceramic veneers (Vident) for the restoration of 5M1 discolored backgrounds. A total of 40 In-Ceram Spinell (SP, n = 20) and Alumina (AL, n = 20) disks (diameter 10.0 mm, thickness 0.4 mm, Vident) were glass-infiltrated under (V, n = 20) or without vacuum (A, n = 20) using a translucent glass (S1, Vident) and then veneered (2M2 Vitadur Alpha, total thickness 0.7mm). The veneer specimens were bonded onto the 5M1 color backgrounds (Vitadur Alpha, diameter 10.0mm, thickness 2.0mm) using a dual curing adhesive cement (Panavia F 2.0 Light, Kuraray), to create the study groups (SPV, SPA, ALV, ALA, each n = 10). Ten 2M2 feldspathic veneer disks (Vitadur Alpha, diameter 10.0mm, thickness 0.7mm) bonded onto 2M2 color backgrounds (Vitadur Alpha, diameter 10.0 mm, thickness 2.0 mm) were used as control (CTR group). L*a*b* color coordinates were measured 5 times for each study group and control specimen using a Vita Easyshade spectrophotometer (Vident). Mean color differences (ΔΕ) were calculated using the equation ΔΕ = (ΔL*2 + Δa*2 + Δb*2)1/2. Mean color differences and standard deviations between each study group and the control group were: 7.31 ± 0.99 for SPV; 7.23 ± 0.61 for SPA; 5.81 ± 1.41 for ALV; and 6.25 ± 0.89 for ALA. Two-way ANOVA followed by t test showed that only the core material had a statistically significant effect on the final color performance (α = .05, P = .000). The core material (Spinell or Alumina) significantly influenced the core-related opacity, while the glass infiltration mode (under or without vacuum) had a minor effect on the final color establishment of both glass-infiltrated veneers over discolored backgrounds. Regarding the reported clinical visible thresholds, In- Ceram Alumina ceramic veneers showed the greatest improvement in the color performance of discolored teeth compared with all other groups.

Ceramics have been used in dentistry and medicine for many years. Today, one of the most popular ceramics is zirconia because of its outstanding mechanical properties, which make it suitable for many indications formerly reserved for metals. Zirconiabased ceramics have been used for many years as the core for single crowns and long-span fixed prostheses. Zirconia-based ceramics have also been used as implants for hip replacements and finger, toe, and wrist joints. Recently, some articles in the dental literature suggest the possible use of zirconia implants for tooth replacement. The present case report illustrates the results that can be achieved using rough-surface zirconia implants in an esthetically demanding case. The 28-year-old male patient required replacement of the maxillary central incisors. Two rough-surface zirconia implants (CeraRoot) were used to immediately replace the extracted teeth. Immediate provisional restorations were placed for a period of 3 months until the final all-ceramic restorations were cemented. Zirconia implants may be a good alternative for tooth replacement, especially in esthetically demanding cases. More studies are needed to evaluate the long-term results of zirconia dental implants with different surfaces.

The purpose of the study was to evaluate the shear bond strengths (SBS) of two resin cements to intaglio surfaces of zirconia from two manufacturers after three surface treatment methods. Forty zirconia specimens from one manufacturer (Lava, 3M ESPE) and 40 zirconia specimens from another manufacturer (Cercon, Dentsply), each with system-specific intaglio surfaces, were randomly divided into four treatment groups (20 samples per group, 10 for each manufacturer): no treatment (No_T), sandblasting with 50µm Al₂O₃ (S_50), sandblasting with 110µm Al₂O₃ (S_110), and Rocatec silica coating and silanization (ESPE-Sil, 3M ESPE) (Roc). A 5-mm metal ring was fixed upon the zirconia and was filled with one of two different resin composite cements (RelyX Unicem, 3M ESPE and Panavia F 2.0, Kuraray). Samples were stored in distilled water at 37°C for 7 days; SBS was evaluated using a universal testing machine. Values were calculated in MPa and the data were analyzed by ANOVA and Tukey HSD test (P < .05). In the Lava specimens, the three surface treatment methods tested did not increase the bond strength of Panavia compared to the control group (P = .195); using RelyX Unicem, S_50 and Roc, mean SBS values were significantly higher than values for No_T (S_50 P = .0048; Roc P < .001). For Lava surfaces treated with Rocatec, there was a statistically significant difference between the two luting cements used (Unicem 11.39 ± 2.19; Panavia 8.56 ± 1.17; P = .002). Regarding the Cercon specimens, there was a significant difference between the Unicem and the Panavia control groups (No_T Unicem 1.48 ± 1.19, No_T Panavia 4.60 ± 2.75, P = .004). In conclusion, all surface treatments increased the bond strength of RelyX Unicem resin cement to both zirconia substrates. No statistically significant changes were found using Panavia on Lava. Sandblasting with 110µm Al₂O₃ provided the highest bond strength for Panavia on Cercon.