Implant prosthodontic design as a predisposing or precipitating factor for peri-implant disease: A review.

Over the past decade, emerging evidence indicates a strong relationship between prosthetic design and peri-implant tissue health. The objective of this narrative review was to evaluate the evidence for the corresponding implant prosthodontic design factors on the risk to peri-implant tissue health. One of the most important factors to achieve an acceptable implant restorative design is the ideal implant position. Malpositioned implants often result in a restorative emergence profile at the implant-abutment junction that can restrict the access for patients to perform adequate oral hygiene. Inadequate cleansability and poor oral hygiene has been reported as a precipitating factors to induce the peri-implant mucositis and peri-implantitis and are influenced by restorative contours. The implant-abutment connection, restorative material selection and restoration design are also reported in the literature as having the potential to influence peri-implant sort tissue health.

Effect of Bonding and Rebonding on the Shear Bond Strength of Two-Piece Implant Restorations.

PURPOSE: To evaluate the rebonding strength of ceramics to titanium alloy after disassembling by heat treatment. MATERIALS AND METHODS: A total of 40 titanium alloy (titanium-6 aluminum-4 vanadium) disks (4.0 × 6.6 mm) and 20 zirconia (Lava Plus) disks were manufactured using computer-aided design and computer-aided manufacturing (CAD/CAM) technology. Twenty heat-pressed lithium disilicate glass-ceramic (IPS e.max Press LT) disks were fabricated and used as controls. Bonding protocol for each specimen surface was performed according to manufacturer's instructions. Specimens (n = 10) of zirconia/titanium alloy (ZR) and lithium disilicate/titanium alloy (LD) were bonded using adhesive resin cement (RelyX Ultimate) and then subjected to a heat treatment (HT, 320°C, 2 minutes) to disassemble the bonding complex, cleaned with aluminum oxide airborne-particle abrasion, and rebonded following the initial protocol, group ZRHT and group LDHT, respectively. After 5000 cycles of thermal cycling, a shear bond test was conducted. A universal testing machine was used at a 5 mm/min crosshead speed. Failed specimens were examined with stereomicroscopy at 10× magnification to identify the mode of failure. One-way ANOVA and Tukey HSD tests were applied for statistical analysis of the shear bond strength data, with statistical significance at α = 0.05. RESULTS: The mean ± SD bond strength values ranged from 28.3 ± 7.2 to 45.9 ± 9.7 MPa. Statistically significant lower shear bond strength values were obtained from the LD group (p = 0.002, F = 5.89), while no statistically significant differences in bond strength were observed between the ZR and ZRHT groups (p > 0.05). Failure mode was predominantly mixed-type failure pattern for all specimens. CONCLUSIONS: Heat and abrasion surface treatment increased the bond strength of lithium disilicate glass-ceramics cemented to titanium alloy, but no effect was observed on zirconia/titanium alloy bonding.

Adhesive residue on the CAD-CAM surgical guide sleeve: A technical report.

Computer-aided design and computer-aided manufacturing (CAD-CAM) surgical guides can be used by the clinician and dental technician to create a definitive cast before surgery, thereby allowing an indirect interim restoration to be fabricated. However, the accurate transfer of the interim restoration from the laboratory to the surgical site requires a precise interface between components. This article reports the prosthetic significance of adhesive residue on the intaglio surface of the CAD-CAM surgical guide sleeve, which can create errors in the implant analog position of the definitive cast. A technique for identifying the presence of residue and its careful removal are also introduced.

A Technique to Correct Anterior-Posterior Tooth Discrepancy for a Maxillary Immediate Complete Denture.

This article describes a chairside technique to correct inappropriate occlusal vertical dimension as well as the inaccurate anterior-posterior tooth set-up of a maxillary immediate complete denture. When fabricating an immediate denture, the inability of a wax-denture trial and the potential for unpredictable complications during surgery, compromised esthetics and function of an immediate complete denture may pose a clinical problem, which needs instant correction. The technique described can provide an alternative method to correct and deliver a definitive immediate complete denture on the day of surgery.

Effect of hydrothermal treatment on light transmission of translucent zirconias.

STATEMENT OF PROBLEM: Studies of the light transmission of translucent zirconias after hydrothermal treatment are limited. PURPOSE: The purpose of this in vitro study was to evaluate the effect of hydrothermal treatment on the light transmission of translucent zirconias for monolithic restorations. MATERIAL AND METHODS: Four commercially available zirconia products, BruxZir Anterior Solid Zirconia (BruxAnt, BA), Lava Plus High Translucency (LPHT), Katana Zirconia Super Translucent (KST), and Katana Zirconia Ultra Translucent (KUT) were assessed and 1 type of lithium disilicate, e.max Press LT (LDLT) was used as a control. Plate specimens, 20×20×1 mm (n=80) for the translucency assessment were sectioned from postsintered zirconia bulk materials and ground with a #400-grit diamond wheel and coolant. The specimens were placed under hydrothermal conditions of 134°C at 0.2 MPa (n=5 per group at 0, 5, 50, and 100 hours). Percentage of total transmittance of light (Tt%) of each specimen was measured using a spectrophotometer with an integrating sphere. X-ray diffraction analyses were used to measure tetragonal-monoclinic phase transformation. Surfaces were examined by scanning electron microscopy and energy dispersive spectrometry. Data were analyzed using 2-way ANOVA followed by the Tukey test (α=.05). RESULTS: The Tt% ranged from 6.5% to 28.3%. Group LDLT obtained significantly higher transmittance than other tested groups, whereas groups KST and KUT had significantly higher Tt% than groups BA and LPHT (P<.05). A statistically significant increase in the amount of monoclinic phase was revealed within all translucent zirconia groups (P<.05), and the increase in group LPHT was significantly higher than those of the other 3 translucent zirconias (P<.05). Minimal changes in the percentages of light transmittance were revealed after 100-hour hydrothermal treatment for all tested translucent zirconias and a lithium disilicate glass-ceramic control. CONCLUSIONS: Hydrothermal treatment had minimal effects on the translucency of translucent zirconias. The tetragonal-monoclinic phase transformation rate of translucent zirconias was found to be low, except in group LPHT.