Screw Access Opening Research Articles

Effects of screw channel angulation on the fracture resistance of one-piece zirconia crown with titanium base.

The design of the angulated screw channel in implant restorations allows the possibility to correct angulation discrepancies, especially in the anterior maxilla. However, the effects of varied screw channel angulations on fracture resistances and fracture patterns of the implant restorations are still uncertain, and thus the aim of this study. Angulated screw channel monolithic zirconia crowns (Nobel Biocare) with three different angulation groups-straight (ASC1), 15° (ASC15), and 25° (ASC25)-were digitally designed from a left central incisor prototype scan. Following fabrication, 10 samples of each group were individually mounted onto implant replicas embedded in standardized type V stone gypsum cylinder jigs (25mm × 25mm). All screws were manually torqued to 35 Ncm according to the manufacturer's recommendation, and screw access openings were subsequently sealed with resin composite. To mimic the off-axis loading of the central incisor, the specimens were then loaded at a cephalometric interincisal relationship of 135° between the long axis of the crown and the Instron force applicator, with crosshead speed set at 0.5mm/min. Fractured abutment surfaces were examined, and selected specimens were further evaluated by scanning electron microscopy. Screw torque values were also measured after the catastrophic loading. One-way ANOVA was used to compare load-to-fracture values between groups, with the statistical significance set at 0.05 (p values). The mean load-to-fracture values in descending order were 331.24N (±34.00N) in ASC15, 325.22N (±35.50N) in ASC25, and 302.04N (±45.10N) in ASC1, with no statistically significant differences between groups. Considerable screw torque losses were found in all groups after catastrophically loading. The average torque loss was 84% in ASC1, 86% in ASC15, and 94% in ASC25. 16 out of 30 specimens experienced screw loosening; one ASC1 screw underwent slight deformation. Crowns of all tested groups exhibited cohesive fracture patterns at the screw-metallic-zirconia interfaces. Within the limitations of this in vitro study, one-piece monolithic zirconia implant crowns with varied screw channel angulations shared similar fracture-strength and fracture-mode characteristics. The zirconia-titanium base junctions exhibited the weakest link of all restorations.

Degree of conversion of light-polymerized composite resin in implant prosthesis screw access opening.

The mechanical and physical properties of implant screw access opening deteriorate if composite resin is not polymerized properly. Therefore, this study aimed to analyze the effect of using composite resin in implant access opening on the degree of conversion (DC). Two prosthetic materials (Co-Cr and zirconia), two types of composite resin (low and high viscosity), two light-cured resin depths (2 and 3mm), and two polymerization methods (max-mode 10s and mid-mode 20s: 16 and 22J/cm2 , respectively) were considered (n=192). The DC of the polymerized composite resin was measured through Fourier-transform infrared spectroscopy. The top and bottom surfaces of the polymerized composite resin body were observed through scanning electron microscopy. Multiple linear regression analysis and analysis of variance were used to identify significant differences in DC (α=0.05). The DC was lower when the low-viscosity composite resin (β=-0.431), light-polymerized resin depth of 2mm (β=-0.430), zirconia prosthesis (β=-0.191), and mid-mode polymerization method (β=-0.164) were used. The resin type, depth of resin to be light-cured, prosthesis material, and polymerization method had an effect on the DC. Low-viscosity composite resin should be polymerized at a low irradiance and long polymerization time (such that the light-cured resin depth does not exceed 2mm) to ensure proper composite resin polymerization in implant screw access opening.

Framework Fracture of Zirconia Supported Full Arch Implant Rehabilitation: A Retrospective Evaluation of Cantilever Length and Distal Cross-Sectional Connection Area in 140 Patients Over an Up-To-7 Year Follow-Up Period.

To evaluate the relationship between different dimensional parameters in implant-supported monolithic zirconia fixed complete dental prostheses (IFCDPs) and the incidence of framework fracture in a large sample of cases in vivo. This retrospective observational study evaluated all patients rehabilitated with screw-retained zirconia IFCDPs between January 2013 and April 2019 at a private practice. The minimum follow-up period was 1 year after occlusal loading. Fractures were classified as: type I-fractures that happened between but not involving the two most posterior screw-access openings (SAOs) and type II-fractures of the distal cantilever. Cantilever length, distal connector cross-sectional area, and screw access opening length were measured using data obtained from digital scans. Logistic regression was performed to evaluate the relationship between types I and II fractures and the independent variables (dimensional parameters). Using the receiver operating characteristic curves, two parameters were identified to be useful for establishing a cut-off and predicting type II fractures. A total of 180 prostheses delivered to 140 patients were analyzed. Five implants failed in three patients: three before delivery of the definitive prostheses and two after. Ten prostheses failed (5.6% prosthetic failure rate): 2 because of implant failures, and 8 because of framework fractures. Five fractures were classified as type I and three as type II. Significant associations were found between cantilever length and type I fractures (Wald = 5.772, df = 1, p = 0.016), distal connector cross-sectional area and type II fractures (Wald = 3.806, df = 1, p = 0.051), and cantilever length and the total number of fractures (Wald = 6.117, df = 1, p = 0.013). Zirconia IFCDPs may be reliable medium-term solutions if some dimensional parameters are followed. The ratios between the cantilever length and cross-sectional connector area should be <0.51, while the ratio between the cantilever length and screw access opening length should be <1.48.

An auxiliary device for screw-retained fixed implant restorations which prevents extrusion of cement into screw-access openings

For screw-retained fixed implant prostheses, the cement that extrudes onto the margin can be easily removed, but the cement that may intrude into the screw-access opening (SAO) during the extraoral bonding process is difficult to eliminate. This article presents a manufactured auxiliary device that is applied to the extraoral bonding process of screw-retained fixed implant prostheses. This device will prevent excess cement from being left in the SAO.

Immediate implant placement and complete mouth rehabilitation with CAD-CAM titanium frameworks and cemented crowns for a patient with severe periodontal disease: A clinical report

The technique of immediate implantation has been widely used to reduce treatment time and bone loss after extraction. However, immediate implant placement in infected extraction sockets is generally contraindicated. This clinical report describes a treatment protocol for immediate implantation after the extraction of teeth with generalized chronic periodontitis. The technique used for the oral rehabilitation used computer-assisted design and computer-assisted manufacturing (CAD-CAM) titanium frameworks and cemented zirconia crowns. The titanium frameworks overcame suboptimal implant position and the cemented crowns provided excellent function and esthetics despite the locations of screw-access openings. No clinical complications occurred during a 13-month follow-up.

A Current Perspective on Screw-Retained Single-Implant Restorations: A Review of Pertinent Literature.

There is a trend toward increased use of screw-retained single-implant restorations. A comprehensive literature review was undertaken to examine the data related to screw- and cement-retention and to objectively evaluate the innovations in implant dentistry that have led to this resurgence. When comparing the two options, survival and complication rates are similar, bone and soft-tissue levels are comparable, and zirconia offers esthetic advantages for both selections. Zirconia abutments with bonded titanium inserts provide esthetic alternatives to titanium abutments for both choices. Bone- and soft-tissue responses are similar, but residual cement of cement-retained restorations is associated with significant soft- and hard-tissue complications. The potential weakness of ceramic discontinuity of screw-access openings can be lessened by the incorporation of stronger ceramic materials such as zirconia and lithium disilicate. The overriding remaining indication for cement-retained restorations is to compensate for angled implants. Screw-retained single-implant crowns should be reconsidered for many clinical situations for the following reasons: Predictable retention and retrievability No potential for the biologic consequences associated with residual cement As with cement-retained restorations, the choice between metal ceramics or all ceramics Only one margin, at the implant/abutment interface A single abutment/crown ceramic margin that can extend gingivally to the implant interface Nearly imperceptible blend of a composite resin in ceramic abutment access openings One component instead of two, which may simplify the restorative process CLINICAL SIGNIFICANCE: Innovations in implant and ceramic technology now give screw-retained prostheses the potential for esthetic, functional, and biologic outcomes that are comparable to those for cement-retained prostheses, while providing the advantages of predictable retrievability and avoidance of residual cement. Angled implants, however, remain a major indication for cement-retained single-implant prostheses. (J Esthet Restor Dent 29:161-171, 2017).

Retrospective 2- to 7-Year Follow-Up Study of 20 Double Full-Arch Implant-Supported Monolithic Zirconia Fixed Prostheses: Measurements and Recommendations for Optimal Design.

To measure the extension of cantilever lengths, thicknesses, and heights of zirconia prostheses in the lingual and facial areas of the distal screw access openings, and to evaluate the clinical performance regarding chipping or fracture of the distal cantilevered sections of double full-arch CAD/CAM screw-retained, stained, monolithic zirconia, gingival-colored ceramic implant-supported fixed prostheses (MZ-FPs). Ten edentulous patients were provided with a total of 20 CAD/CAM double full-arch MZ-FPs. The zirconia thicknesses around distal screw access openings at three different levels (crown height space, screw access opening lengths, and dimensions of the cantilevered segments) were measured in the resin prototypes. Patients were evaluated clinically (visually) without magnification, with intraoral digital photography, and radiologically by the author, approximately every 6 months. Ten patients with 20 MZ-FPs were evaluated. Twenty resin prototypes with 35 cantilevered segments (15 maxillary, 20 mandibular) were measured. The lingual and facial thicknesses of the resin frameworks and the crown height spaces of 35 distal access openings were measured. The average extension of the maxillary cantilever segments was 7.72 mm; the mandibular cantilever average was 13.72 mm. The average crown height space for maxillary prostheses was 13.27 mm, for the mandibular prostheses it was 11.89 mm. Zirconia thickness around distal screw access openings at the middle of the crowns, margins and middle of the gingival areas (buccal side of maxillary prostheses) was 4.29, 3.79, and 3.87 mm, respectively. On the lingual sides the thicknesses were 3.13, 2.85, and 3.15 mm, respectively. For mandibular prostheses the thicknesses were 3.56, 3.08, and 3.15 mm, respectively, on the buccal sides, and 2.07, 2.00, and 2.99 mm, respectively, on the lingual sides. No implant failure or changes in the occlusal surface, chipping of the cuspid or incisal edges, or prosthesis distal extension fractures were observed during follow-up periods ranging from 2 to 7 years. The survival rate was 100% for implants and prostheses. In one of the patients, chipping of the pink ceramic was noted in the maxillary prosthesis 36 months after placement. The results of this study indicated that full-arch MZ-FPs without cutback, or with partial digital cutback and veneering ceramic, were a therapeutic option. Recommendations regarding the thickness of zirconia at the level of the distal screw access openings, the crown height spaces, and the lengths of the cantilever segments were recorded. Additional in vitro and clinical studies will be required for more scientific analysis of the criteria for design of this type of prosthesis to minimize prosthetic complications. Long-term and multicenter studies are needed to corroborate the findings discussed in this report.

Effect of Preseating, Screw Access Opening, and Vent Holes on Extrusion of Excess Cement at the Crown-Abutment Margin and Associated Tensile Force for Cement-Retained Implant Restorations.

This study sought to (1) compare the effects of crown preseating prior to cementation, (2) determine whether maintenance of screw access openings on titanium abutments and open vent holes on cast crowns affects the amount of excess cement at the crown-abutment margin, and (3) analyze the associated tensile force after cementation. Three independent variables were tested: (1) abutment screw access (open or closed), (2) crown coping modification (with or without a vent hole in the palatal aspect), and (3) crown preseating on an abutment analog. Ten implant crown copings were cemented using temporary cement on ten straight implant abutments for each combination of the three independent variables. The amount of excess cement at the crown margins was measured by weight. Axial tensile load was measured 24 hours after cementation. Results were statistically analyzed using linear regression and univariate three-way analysis of variance (α = .05). Open screw access, presence of a vent hole on the crown, and preseating of the crown had significant effects on the amount of excess cement at the crown margin (P < .05). Preseating significantly lowered tensile strength values (P = .001), particularly in specimens with preseating and open screw access (P < .001). There was no significant correlation between excess cement at the margins and tensile strength values. Placement of vent holes on the crown or open screw access may be considered for cementing crowns on implant abutments using temporary cement in order to minimize excess cement at the crown margin. A preseating protocol is not advisable, either alone or combined with open screw access, since it significantly reduces the retentive strength of cemented restorations (P < .001).

Fabrication of a screw-retained restoration avoiding the facial access hole: A clinical report

Dental implant restorations may be either screw-retained or cemented onto an abutment. While each method has its advantages and disadvantages, cemented restorations are commonly used in the maxillary arch, usually because of esthetic concerns. Available bone in the anterior maxilla dictates the placement of the implant, which may result in a facially positioned screw-access opening. Still, a growing volume of literature states that periimplant soft tissues respond more favorably to screw-retained crowns than cement-retained crowns. This clinical report outlines a treatment with a new method of fabricating a custom abutment-crown combination for a screw-retained restoration. The technique allows the channel for the screw to be placed at an angle other than parallel to the implant body. In this case, the practitioner may choose either a screw-retained or cement-retained implant restoration, where previously only a cemented restoration was possible.

A simple procedure for retrieval of a cement-retained implant-supported crown: A case report

Retrieval of cement-retained implant prostheses can be more demanding than retrieval of screw-retained prostheses. This case report describes a simple and predictable procedure to locate the abutment screw access openings of cementretained implant-supported crowns in cases of fractured ceramic veneer. A conventional periapical radiography image was captured using a digital camera, transferred to a computer, and manipulated using Microsoft Word document software to estimate the location of the abutment screw access.

A technique for the management of screw access opening in cement-retained implant restorations

Introduction: Abutment screw loosening has been considered as a common complication of implant-supported dental prostheses. This problem is more important in cement-retained implant restorations due to their invisible position of the screw access opening. Case Report: This report describes a modified retrievability method for cement-retained implant restorations in the event of abutment screw loosening. The screw access opening was marked with ceramic stain and its porcelain surface was treated using hydrofluoric acid (HF), silane, and adhesive to bond to composite resin. Discussion: The present modified technique facilitates screw access opening and improves the bond between the porcelain and composite resin.

Occlusal-view photograph of a cement-retained implant prosthesis as a permanent guide for access-hole preparation

Implant-supported fixed restorations can be screw-retained or cement-retained. Pjetursson et al 1 Pjetursson BE Brägger U Lang NP Zwahlen M Comparison of survival and complication rates of tooth-supported fixed dental prostheses (FDPs) and implant-supported FDPs and single crowns (SCs). Clin Oral Implants Res. 2007; 18: 97-113 Crossref PubMed Scopus (560) Google Scholar and Papaspyridakos et al 2 Papaspyridakos P Chen CJ Chuang SK Weber HP Gallucci GO A systematic review of biologic and technical complications with fixed implant rehabilitations for edentulous patients. Int J Oral Maxillofac Implants. 2012; 27: 102-110 PubMed Google Scholar observed that the most frequent technical complications with implant restorations were fracture or chipping of the veneer ceramic, abutment or screw loosening, screw fracture, and loss of retention. These complications necessitate the restorations to be removed, repaired, and reinserted as needed. For removal of cement-retained implant prostheses, it is necessary to access the abutment from the occlusal surface. Locating the site of entry for access-hole preparation to the abutment-screw has been described by several authors. 3 Doerr J Simplified technique for retrieving cemented implant restorations. J Prosthet Dent. 2002; 88: 352-353 Abstract Full Text Full Text PDF PubMed Scopus (41) Google Scholar , 4 Tarlow JL A modified technique to locate the abutment screw access opening of a cemented implant-supported restoration. J Prosthet Dent. 2012; 108: 58-59 Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar , 5 Hill EE A simple, permanent index for abutment screw access for cemented implant-supported crowns. J Prosthet Dent. 2007; 97: 313-314 Abstract Full Text Full Text PDF PubMed Scopus (12) Google Scholar , 6 Schwedhelm ER Raigrodski AJ A technique for locating implant abutment screws of posterior cement-retained metal-ceramic restorations with ceramic occlusal surfaces. J Prosthet Dent. 2006; 95: 165-167 Abstract Full Text Full Text PDF PubMed Scopus (45) Google Scholar , 7 Figueras-Alvarez O Cedeño R Cano-Batalla J Cabratosa-Termes J A method for registering the abutment screw position of cement-retained implant restorations. J Prosthet Dent. 2010; 104: 60-62 Abstract Full Text Full Text PDF PubMed Scopus (26) Google Scholar Doerr 3 Doerr J Simplified technique for retrieving cemented implant restorations. J Prosthet Dent. 2002; 88: 352-353 Abstract Full Text Full Text PDF PubMed Scopus (41) Google Scholar and Tarlow 4 Tarlow JL A modified technique to locate the abutment screw access opening of a cemented implant-supported restoration. J Prosthet Dent. 2012; 108: 58-59 Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar explained an access-gaining technique by using a vacuum-formed matrix with holes corresponding to abutment positions in which the clinician must preserve the original casts or a vacuum-formed matrix. Hill 5 Hill EE A simple, permanent index for abutment screw access for cemented implant-supported crowns. J Prosthet Dent. 2007; 97: 313-314 Abstract Full Text Full Text PDF PubMed Scopus (12) Google Scholar described preservation of a putty index for the same reason. Schwedhelm and Raigrodski 6 Schwedhelm ER Raigrodski AJ A technique for locating implant abutment screws of posterior cement-retained metal-ceramic restorations with ceramic occlusal surfaces. J Prosthet Dent. 2006; 95: 165-167 Abstract Full Text Full Text PDF PubMed Scopus (45) Google Scholar described a technique which requires placement of a small ceramic stain on the occlusal surface of the restoration during fabrication. Figueras-Alvarez et al 7 Figueras-Alvarez O Cedeño R Cano-Batalla J Cabratosa-Termes J A method for registering the abutment screw position of cement-retained implant restorations. J Prosthet Dent. 2010; 104: 60-62 Abstract Full Text Full Text PDF PubMed Scopus (26) Google Scholar advocated the preservation of a photograph in a computer file as part of the patient's permanent record; however, it involved using complex editing software to superpose 2 digital photographs of the definitive cast with and without the restoration.

Three‐Dimensional Location of the Retaining Screw Axis for a Cemented Single Tooth Implant Restoration

Retrievability is a major concern with cemented versus screw-retained implant restorations. This article describes the use of cone beam radiography to help target and create a precise screw access opening for a loosened implant-supported single crown retained by cement to its abutment.

A modified technique to locate the abutment screw access opening of a cemented implant-supported restoration

Cemented implant-supported restorations have advantages relative to those which are screw retained, including greater passivity of fit and better esthetics.1 However, the easier retrievability of a screw-retained restoration is clinically useful should an abutment screw become loose. Abutment loosening of a cemented implant crown usually necessitates estimating the location of the abutment screw access opening, and accessing the screw by drilling through the crown. Several articles have been written describing methods for indicating the location of the abutment screw, either prior to or after the restoration has been cemented.

Porcelain Fracture Resistance of Screw‐Retained, Cement‐Retained, and Screw‐Cement‐Retained Implant‐Supported Metal Ceramic Posterior Crowns

The purpose of this in vitro study was to compare the porcelain fracture resistance between screw-retained, cement-retained, and combined screw- and cement-retained metal-ceramic (MC) implant-supported posterior single crowns; and to investigate the effect of offsetting the occlusal screw-access opening on porcelain fracture resistance of screw-retained and cement-retained MC implant-supported posterior single crowns. Forty standardized MC molar-shaped restorations were fabricated. The 40 restorations were divided into four groups (SRC, SRO, CRP, and CSC) of 10 specimens each. Group SRC: screw-retained, screw-access hole placed in the center of the occlusal surface; Group SRO: screw-retained, screw access hole placed 1 mm offset from the center of the occlusal surface toward the buccal cusp; Group CRP: cement-retained, zinc phosphate cement was used; Group CSC: cement-retained with a screw-access hole in the center of the occlusal surface. The screw-retained restorations and abutments were directly attached to 3i implant fixtures embedded in acrylic resin blocks. Subsequently, all test specimens were thermocycled and vertically loaded in a universal testing machine at a crosshead speed of 2 mm/min until fracture. Mean values of load at fracture (in N) were calculated in each group and compared with a one-way ANOVA and Tukey's Studentized test (alpha= 0.05). Mean values of loads required to fracture the restorations were as follows (N): Group SRC: 1721 +/- 593; Group SRO: 1885 +/- 491; Group CRP: 3707 +/- 1086; Group CSC: 1700 +/- 526. Groups SRC, SRO, and CSC required a significantly lower force to fracture the porcelain than did the CRP group (p < 0.05). The cement-retained restorations showed significantly higher mean fracture loads than the restorations having screw-access openings in their occlusal surface. The position of the screw-access hole within the occlusal surface did not significantly affect the porcelain fracture resistance.

Survey of United States dental schools on cementation protocols for implant crown restorations

With conflicting results in the literature and various manufacturer recommendations, it is not known what cementation protocols are currently being used for implant restorations in US dental schools. The purpose of this survey was to determine what dental cementation protocols are taught and recommended by 62 US dental schools and postgraduate programs. From February to September 2008, 96 questionnaires consisting of 8 questions were sent to the chairperson or director of restorative departments, advanced prosthodontics programs, and implant programs. The questionnaire asked recipients which implant manufacturers provided the products used at their dental schools. Additionally, recipients were queried as to the choice of material and techniques for abutment and restoration preparations prior to definitive cementation. Data were analyzed with descriptive statistics. A total of 68 (71%) surveys were returned, and 52 (84%) of the 62 predoctoral and postgraduate programs were represented. After deleting duplicate responses, 31 surveys were returned from restorative department chairpersons, 29 from advanced prosthodontic program directors, and 2 from implant program directors. Frequency of responses to each question was tabulated, and results are presented in 3 sections. For all 3 types of programs, Nobel Biocare was reported to be the most widely used implant system, followed by Biomet 3i, Straumann, Astra Tech, and Zimmer Dental systems. The most commonly used technique prior to definitive cementation is to airborne-particle abrade the intaglio surface of the restoration. Resin-modified glass ionomer is the most frequently used luting agent for cementing implant restorations. The 5 most commonly used materials to fill screw access openings are cotton pellets, composite resin, rubber-based material, gutta-percha, and light-polymerized provisional composite resin. Most predoctoral and postgraduate programs teach students to fill the screw access opening completely to the occlusal surface. There are a wide range of implant cementation protocols and materials used; however, some common trends were identified among predoctoral and postgraduate programs.

Edentulous Arch Treatment With a CAD/CAM Screw-Retained Framework and Cemented Crowns: A Clinical Case Report

This article describes the rehabilitation of a completely edentulous patient using a milled titanium implant framework and cemented crowns. This combined approach significantly offsets unsuitable implant position, alignment, or angulation, while ensuring the easy retrievability, repair, and maintenance of the prosthesis. Hence, the dual advantage of cemented-retained crowns reproducing appropriate esthetics and function, irrespective of where the screw access openings are located in the substructure, can be obtained, along with the splinting effect and management of soft and hard tissue deficits achievable with a screw-retained framework.

The use of digital photographs to locate implant abutment screws for implant-supported cement-retained restorations

aAssociate Professor, Department of Restorative Dentistry, Loma Linda University. bProfessor and Director, Division of Postdoctoral Prosthodontics, Department of Restorative Sciences and Biomaterials, Goldman School of Dental Medicine, Boston University. (J Prosthet Dent 2008;100:238-239) Cement-retained implant-supported restorations are commonly used, and have advantages and disadvantages. Retention of implantsupported crowns by using cement eliminates unesthetic screw access openings. Another advantage is the potential to compensate for minor dimensional discrepancies in the fit of multiunit restorations by using cement and the cement space.1 However, cemented implant-supported crowns are more difficult to retrieve for subsequent maintenance.1 If the location of the access screw opening is not known, the removal of a cement-retained implant-supported restoration with a loose abutment screw or fractured porcelain may result in difficulties and perhaps irreversible damage to the restoration or the abutment. Several methods have been described in the literature to provide retrievability of cemented implant-supported restorations. One approach is the use of provisional cement. The argument that cements of differing retentive capacities can be titrated to somehow function as effectively as screws for either removal or retention has been challenged.1 A second method is the use of set screws that allow a retrieval screw to be placed in a position where a displacing force can be applied in the direction of the abutment to break the cement seal and allow removal of the restoration.2 The disadvantage of this technique is the access opening in the occlusal surface for the extra screw needed to remove the crown. A third approach is the placement of a well-defined small ceramic stain on the occlusal surface of a posterior implant-supported restoration in conjunction with a periapical radiograph for evaluating the implant angulation. This method provides a reliable landmark for locating the screw-access opening of the abutment.3 However, this technique is limited to posterior implant-supported restorations only, and the ceramic stain can only be placed in nonesthetic areas. A fourth approach is the use of a secondary lingual locking screw in the restoration for retention and retrievability.4 A fifth approach is the use of cylindrical guide holes in the lingual aspect of implant-supported restorations for the removal of cemented superstructures.5 A removing driver placed in these guide holes, when turned, creates a shear force and thereby raises and unseats the restoration. A sixth method is the use of a vacuum-formed clear retaining screw location guide, similar to a surgical guide, made on a cast. The location guide assists in locating the implant abutment access chamber and abutment retaining screw to facilitate the removal of a cemented implant-supported restoration.6 The disadvantage of this technique is the need to retain the original implant and abutment level casts. This article describes an uncomplicated technique to facilitate the removal of a cemented implant-supported restoration. This technique has 2 advantages: it will not damage the implant abutment, and the patient’s visit will be relatively brief. After seating the implant abutment(s) (Cast-to Gold Abutment, engaging; Zimmer Dental, Carlsbad, Calif ) and the implant-supported restoration(s), a series of digital photographs are made with a digital camera (Dine Pentax Digital Solution; Lester A. Dine, Inc, Palm Beach Gardens, Fla) with the use of the intraoral macro setting.

The use of customized implant frameworks with gingiva-colored composite resin to restore deficient gingival architecture

This article describes a technique for fabricating cement-retained crowns over a customized gingiva-colored composite resin screw-retained implant infrastructure. This prosthetic design is not significantly influenced by unsuitable implant position, alignment, or angulation. Consequently, the cement-retained crowns can be reproduced in an esthetically and functionally appropriate morphology, regardless of where the screw-access openings are located in the infrastructure.

A time-saving technique for selection, insertion, and provisional restoration of angulated abutments for dental implants

Angulated abutments are useful in correcting some malpositioned or misaligned implants. However, selection of angulated abutments at chairside may be difficult. Each abutment must be selected taking into consideration the esthetics, contour, and occlusion of the definitive restoration. When inserting an angulated abutment, the ultimate position will also affect the location of the future screw access opening. If not oriented properly, another appointment for reseating the abutment and impression making may be required. A screw-retained provisional implant-supported prosthesis can be efficiently fabricated in the laboratory after the definitive impression has been made. A simple technique is presented to save chairside time and reduce the number of appointments while requiring only minimal materials and components.