The distribution of marginal excess cement of implant-supported vented and non-vented zirconia crowns with and without cleaning procedures.

PURPOSE: To investigate the distribution of marginal excess cement in vented and non-vented crowns and evaluate the effect of clinical cleaning procedures on the reduction of excess cement. MATERIALS AND METHODS: Forty models with implant analogs in the position of the right maxillary first molar were divided into four groups (n = 10/group, vented/non-vented crowns with or without cleaning procedures). The abutment finish lines were placed 1 mm below the artificial gingiva buccally, mesially, and distally and at the gingival level palatally. A standardized amount (20 mg) of resin cement was applied in a thin layer to the intaglio surface of zirconia vented and non-vented crowns. The excess cement was removed by a dental explorer in groups with cleaning procedures. The distribution (area and depth) of the marginal excess cement was measured at each quadrant (buccal, mesial, palatal, and distal) for all study samples. The data were analyzed using descriptive and analytical statistics (ɑ = 0.05). RESULTS: The area and depth values of the excess cement in each quadrant in the vented group were significantly smaller than that in the non-vented group, both with and without cleaning (p < 0.001). Cleaning procedures significantly reduced the area of excess cement in both vented and non-vented groups (all, p < 0.001 except for p < 0.05 at the buccal aspect of the vented group). The depth of excess cement in the vented group was significantly decreased with cleaning in the buccal quadrant compared with that without cleaning (p < 0.01). However, the depth of excess cement of the non-vented group was significantly increased with cleaning in all quadrants compared with that without cleaning (all, p < 0.001 except for p < 0.05 at the distal aspect). CONCLUSIONS: Crown venting significantly reduced the area and depth of the marginal excess cement in vitro. Cleaning procedure with a dental explorer significantly reduced the area of marginal excess cement in vitro; however, the excess cement can be pushed deeper in the non-vented group.

Evaluation of the marginal excess cement and retention force of implant-supported zirconia crowns with various vent designs under different cement application patterns.

OBJECTIVE: To investigate the effects of implant-supported zirconia crowns with various vent designs on the marginal excess cement (MEC) and retention values under different cement application patterns. MATERIALS AND METHODS: Cercon zirconia crowns (n = 36) were divided into the following groups: no venting (NV group), a small occlusal vent hole (SOV group), a large occlusal vent hole (LOV group), and a small palatal-occlusal vent hole (SPV group). The cement was applied to the crowns with different methods: occlusally half axial walls (OH), cervically half axial walls (CH) and all axial walls (AA), and different amounts of cement were applied with a chosen method. The weight of the MEC was calculated, and the retention force was recorded. ANOVA was used to analyze the MEC weights and retention values. RESULTS: In all vented groups, the OH application method resulted in no MEC and the least retention force, and the AA method expressed significantly less MEC (p < 0.01) than the CH method without retention force reduction. At each amount of cement (5, 10, 20, 30 mg), all three venting designs significantly reduced the MEC by the AA method, and the mean MEC of the LOV group was lower than that of any other group. CONCLUSIONS: Applying a thin layer of cement evenly to all axial walls of vented zirconia crowns showed excellent clinical effects regarding the MEC and the retention force. CLINICAL SIGNIFICANCE: Residual excess cement was identified as a possible risk indicator for peri-implant diseases. Simply and effectively minimizing marginal extrusions without reducing the retention force has clinical value. The results of this study indicate that applying a thin layer of cement evenly to all axial walls of vented zirconia crowns is an acceptable method.

Access to abutment screw in cement retained restorations: a clinical tip.

Abutment screw loosening has been reported to be the most common prosthetic complications occurring in screw retained as well as cement retained implant restorations. Different methods to treat this issue have been reported in the literature so far; however these have their own short-comings. Retrievability of an implant restoration intact becomes a clinical challenge when the restoration is cement retained especially with an angulated abutment. This technique is aimed at accurately determining the position of the abutment screw in 3 dimensional relationships using a vacuum formed clear stent. This technique can be used as a viable protocol for management of screw loosening in cement retained implant restorations.

Replacement of missing anterior tooth using screw retained implant prosthesis in the esthetic zone: a case report with 3 years of follow up.

As more and more dental practitioners are focusing on implant-supported fixed restorations, some clinicians favor the use of cement retained restorations while others consider screw-retained prosthesis to be the best choice. As both types of prostheses have certain advantages and disadvantages, clinicians should be aware of the limitations of each type. Screw-retained implant restorations have an advantage of predictable retention, retrievability and lack of potentially retained sub-gingival cement. However, a few disadvantages exist such as precise placement of the implant for optimal and esthetic location of the screw access hole and obtaining passive fit. On the other hand, cement retained restorations eliminates unaesthetic screw access holes; have passive fit of castings; reduce stress to splinted implants because of minor misfit of the framework; reduced complexity of lab procedures; enhanced esthetics; reduced cost factors and non disrupted morphology of the occlusal table. This case report presents the replacement of missing left central incisor using screw-retained implant prosthesis due to palatal trajectory of the implant placement and inadequate abutment height for retention of cement retained prosthesis.

Utilización de una guía para el posicionamiento de prótesis fija cementada sobre implantes: relato de un caso clínico / Use of guide to positioning of cement-retained implant protheses: case report

Actualmente el uso de prótesis sobre implantes se incrementó gradualmente desde el descubrimiento de la oseointegración. La indicación inicial de los implantes fue para pacientes edéntulos totales extendiéndose después para pacientes parcialmente edéntulos. Las alternativas de retención de las piezas protésicas van desde las prótesis atornilladas hasta las prótesis cementadas o por preparación de los pilares de la forma convencional. Las prótesis cementadas sobre implantes se utilizan frecuentemente en los casos donde la inclinación de los implantes imposibilita la confección de prótesis atornilladas, debido a la salida de los tornillos de fijación por vestibular o entre los espacios interdentales comprometiendo la estética, y la resistencia cuando están localizados en las cúspides oclusales de los dientes posteriores. En ese sentido, la confección de "copings" en los pilares preparados, puede tornar el tratamiento en un proceso más rápido y seguro. No obstante, pueden surgir problemas en el momento de la instalación, debido a que el intermediario puede asumir diversas posiciones en relación a la posición del implante dificultando la colocación de la prótesis definitiva, principalmente en situaciones clínicas con más de dos implantes. De este modo, el objetivo de este trabajo fue mostrar una técnica del uso de una guía para posicionamiento de los pilares protésicos en prótesis fija cementada sobre implantes, por medio de la descripción de un caso clínico

Nowadays, the use of implant-retained prostheses has been increasing progressively since the advent of the osseointegration. The basic indication was in total edentulous patients and it was also enlarged for partially edentulous patients. Alternatives of retention could be from screw-retained implant prostheses, cement-retained implant prostheses or conventional preparations. Cement-retained implant prostheses are used frequently when the implant inclination don't allow the use of screw-retained prostheses because the screw emerge in vestibular surface or the interdental space resulting in an unaesthetic appearance and when the screw emerge on the top of the posterior cuspid teeth, diminishing the resistance. The confection of the copings on the abutments, turn the treatment faster and secure. Although, some complications can appear in the placement, because the abutment can take different positions in relation to the implant modifying the set of the prosthesis, mainly in clinical situations with more than two implants support. Thus, the aim of this study was demonstrated the use of guide to positioning of cement-retained implant prostheses, by means of a clinical case