Dentists' Perspective and Experiences Relative to the Accidental Dropping of Implant Drivers and Components Intraorally: A Survey of Practicing Clinicians.

Ingestion or aspiration of dental implant screwdrivers or implant components is potentially life-threatening. There are no reports on the frequency at which dentists drop these devices within the mouth or which components are most problematic. There are few reports on what protective measures clinicians take, where risks exist, and how this problem is managed. A 9-part questionnaire was provided to dentists. Data collected included clinicians' roles, implant surgeons, restorative clinicians, or both-the frequency of dropping implant screwdrivers or components, items considered most problematic. Patient protection and management were also requested. Finally, questions related to how much of a problem clinicians considered this to be and if further solutions and a standardized management protocol should be developed. One hundred twelve dentists voluntarily completed the survey. Of the dentists, 54% restored, 37% restored and surgically placed, and 9% solely placed implants. Twenty-nine percent claimed never to drop components, with 56% dropping an instrument less than 10% of the time. Less than half would suggest patients seek medical advice if a screwdriver or component was accidentally dropped intraorally and was not recovered. Thirty percent never tied floss tethers to screwdrivers, and a similar percentage reported they only sometimes did so. Throat pack protection was reported 51% of the time. Ninety percent considered dropping components an issue, with screwdrivers most problematic. Aspiration or ingestion of implant screwdrivers and components is problematic, with dentists varying their use of protection devices. There is a need to standardize and implement patient protection procedures and management and develop methods to reduce the risk of these potentially life-threatening issues.

Effect of viewing angles on measurement errors when using an implant cantilever beam torque-limiting device.

STATEMENT OF PROBLEM: Implant cantilever beam torque-limiting devices are affected by parallax, which may result in measurement read error. The overread or underread of the true target torque value could lead to premature failure of the screw joint of a dental implant. PURPOSE: The purpose of this in vitro study was to determine the effect of the operator's viewing angle relative to the cantilever beam and measurement reading scale when the torque-limiting device is actioned toward or away from the operator. MATERIAL AND METHODS: A beam torque wrench (Nobel Biocare USA) was used with the cantilever beam position fixed by using a wedge to read 32 Ncm on the marker arm. It was suspended in a vertical position relative to a digital single-lens reflex camera set at a fixed distance of 48 cm from the marker reading. The camera was rotated in 10-degree increments clockwise and counterclockwise relative to the cantilever beam reading, starting perpendicular to the marker. Photographs were recorded at each angle. Percentage measurement read error was calculated from dimensions of the cantilever beam torque device, including the beam diameter, distance from the marker arm, and the incremental marks on the measurement scale. Data were analyzed descriptively to determine the differences after comparison with the International Organization for Standardization (ISO) 6789-1:2017 recommendations. RESULTS: Photographs compared beam position relative to the 32-Ncm marker. The beam diameter was recorded as 1.5 mm, corresponding to approximately 5 Ncm. The distance between the marker arm and center of the beam was 0.08 mm. Percentage errors were greatest at lower torque values and increased relative to the viewing angle. Photographs showed that instrument overread was most likely to occur as the beam was moved away from the operator, which would result in potential undertightening unless compensated for. Underread was noted when the beam was pulled toward the operator. CONCLUSIONS: To prevent measurement read error when using an implant cantilever beam torque-limiting device, the operator should be positioned as close to a perpendicular viewing angle to the cantilever beam as possible. Viewing from an angle greater than 10 degrees from the perpendicular should be avoided for torque values less than 15 Ncm. For screws tightened between 25 Ncm and 35 Ncm, the viewing angle should be less than 30 degrees so that the applied torque is within the maximum deviation of the target torque value set by the ISO 6789-1:2017 recommendations.

Effect of implant abutment screw materials and tightening protocols on reverse tightening values: An in vitro study.

STATEMENT OF PROBLEM: Implant abutment screw loosening is the most common prosthetic complication of implant-supported single crowns. However, few studies have objectively evaluated the effectiveness of different tightening protocols on reverse tightening values (RTVs). PURPOSE: The purpose of this in vitro study was to determine the optimal tightening protocol for implant abutment screws with different screw materials. MATERIAL AND METHODS: Sixty implants from 2 implant systems (Keystone and Nobel Biocare) with different definitive screw materials were selected. One group used diamond-like carbon (DLC) coated screws (DLC Group), and the other used titanium nitride (TiN) screws (TiN Group). Each group consisted of 30 implants. The implants in each group were distributed randomly into 3 subgroups (n=10). The implants from both manufacturers were mounted in resin blocks by following a clinical component connection protocol: a cover screw was placed, then an impression coping, and finally an original manufacturer prefabricated abutment. The abutment screws were tightened to the manufacturer's recommended tightening value using 3 different protocols: tighten the screw once (1T); tighten the abutment screw to the recommended tightening value, wait 10 minutes, and then retighten (2T); and tighten the abutment screw to the recommended tightening value, countertighten, tighten, countertighten, and then tighten (3TC). RTVs were measured after 3 hours. The Shapiro-Wilk test was performed to test for normal distribution of the data. The Kruskal-Wallis test was applied to each system's group that was not normally distributed (P<.05). Where differences existed, a post hoc analysis using the Dwass-Steel-Critchlow-Flinger (DSCF) pairwise comparisons test was conducted. RESULTS: No significant differences were found among the 3 different tightening groups in the TiN group (P>.05). However, significant differences were found among the 3 different tightening protocols in the DLC group (P<.05). CONCLUSIONS: Abutment screw systems from different manufacturers behave differently with respect to how they are tightened. For the TiN screw group, statistically similar RTVs were found for the 3 tightening protocols. The most efficient tightening protocol for the DLC-coated screw was the 3TC-DLC.

Effect of activation rate on output torque values from a dental implant toggle-style torque wrench.

STATEMENT OF PROBLEM: The output torque delivered by a dental implant toggle-style torque wrench is known to be affected by activation rate. The International Organization for Standardization (ISO) established the ISO 6789-1 standard to provide guidance on activation rates relative to desired output torque in the Nm torque range. Whether the ISO 6789-1 standard applies at the relatively lower dental torque ranges is not known, and little information is available on the activation rates that clinicians use and how this may affect output torque. PURPOSE: The purpose of this in vitro study was to determine how output torque values vary with the activation rates used by clinicians at dental implant-relevant target torque values. MATERIAL AND METHODS: To determine clinically relevant activation rates, a new adjustable dental implant toggle-style torque wrench was activated from 0 to 25 Ncm target torque by 5 prosthodontists by using a custom mandibular and maxillary typodont model containing implants and abutments with screws. This provided a baseline of activation rates (mm/sec). Data were transferred to a computerized numerical control model incorporating a variable speed linear motor, which was used to drive a dental implant toggle-style torque wrench attached to an electronic torque measuring device. Constant speed and a regulated dual-speed-assigned 80/20 rate group, where 80% of target torque value was delivered first, then a pause, and the final 20% at different speeds as suggested by the ISO 6789-1 standard, were evaluated. Fast, medium, and slow rates were categorized and applied with target torque values of 10, 25, and 35 Ncm, respectively, for n=12 activations. The output torque values were recorded for both constant and 80/20 groups and compared with the desired target torque values. Data were statistically analyzed with 1-way ANOVA and the Scheffé post hoc paired t test (α=.05). RESULTS: The clinicians' activation rates from 0 to 25 Ncm on the typodont model converted into linear speeds resulted in fast =24.19 mm/sec, medium =14.5 mm/sec, and slow =7.25 mm/sec. When actioned at a constant rate, the mean output torque values were generally in the order of slow > medium > fast in activation rates. Generally, precision output torque decreased as target torque increased, especially when slow and medium rates, either constant or regulated 80/20 were used. All mean output torque for slow, medium, and their 80/20 variants were greater than target torque. Fast and 80/20 fast produced the lowest mean output torque values for all torque settings, and at the 35 Ncm setting, the dental implant toggle-style torque wrench output torque mean values were lower than target torque. Statistically significant differences (P<.05) were found among groups, most notably in the 80/20 dual-speed groups, especially in comparisons with the 80/20 fast rate group. When the target torque value was 10 Ncm with the 80/20 fast rate, the output torque value deviated from the maximum ISO limit by more than 6%. CONCLUSIONS: The rate of actioning a dental implant toggle-style torque wrench influenced the delivered torque value, with fast rate actioning producing lower and less precise output torque values.

Evaluating the effect of the protector cap for castable implant abutments on reverse tightening values.

STATEMENT OF PROBLEM: Screw loosening is the most common mechanical complication with implant prostheses. How the alteration of implant-to-abutment connection surfaces that occurs during laboratory procedures affects screw loosening is unclear. PURPOSE: The purpose of this in vitro study was to compare the reverse tightening value (RTV) differences between custom castable abutments before casting, after casting in a conventional manner, and after casting with custom protector caps and pegs. MATERIAL AND METHODS: Thirty implants with a standard-diameter conical connection (NobelReplace Conical Connection 4.3×13 mm; Nobel Biocare AG) and 30 premachined 4.3-mm GoldAdapt abutments (GoldAdapt; Nobel Biocare AG) were selected for this study. Specimens were divided into 3 groups (n=10): the uncast custom castable abutment group (UCCA) in which abutments were new and not cast; the unprotected custom castable abutment group (UPCCA) in which abutments were cast and devested with airborne-particle abrasion; and the protected custom castable abutment group (PCCA) in which abutments were cast by using protector caps and pegs made by milling zirconia and then devested with airborne-particle abrasion. All abutments in each group were tightened to 35 Ncm with a calibrated digital tightening device. After 10 minutes, all screws were retightened to 35 Ncm. At 3 hours, each screw was loosened, and the value at which the initial loosening occurred was documented as the RTV. The results were statistically analyzed with 1-way ANOVA to explore differences, and post hoc tests with Tukey adjustment were used for multiple comparisons. RESULTS: Among the tested groups, the mean RTV ranged from 19.89 Ncm to 27.19 Ncm: UCCA 27.19 Ncm, UPCCA 19.89 Ncm, and PCCA 24.24 Ncm. A significant difference was found among the tested groups (P<.05). CONCLUSIONS: Casting procedures, especially devestment with airborne-particle abrasion, affected implant-abutment connections and the seat site of the screw. Protecting the implant connection site and the seat site of the abutment screw with protector caps and pegs prevented a significant loss of the RTV.

Evaluation of implant abutment screw tightening protocols on reverse tightening values: An in vitro study.

STATEMENT OF PROBLEM: Implant abutment screw loosening is a common prosthetic complication of implant-supported crowns. However, reports that have objectively evaluated the effectiveness of different tightening protocols on reverse tightening values are sparse. PURPOSE: The purpose of this in vitro study was to determine the optimal tightening protocol for implant abutment screws. MATERIAL AND METHODS: Fifty Neoss implants were randomly distributed to 5 groups (n=10). The implants received a cover screw and mounted, and the impression coping was tightened. Tightening was measured by using a digital measuring device. Then, the implant abutments were placed and tightened to 32 Ncm by using a Crystaloc screw. In Group 2T10I, the screws were tightened twice with an interval of 10 minutes between the first and second tightening. In Group 2T0I, the screws were tightened twice with no interval time. In Group 1T, the screws were tightened 1 time only. In Group TCT, the screws were tightened, counter-tightened, and then tightened again. In Group TCTCT, the abutment screws were tightened, counter-tightened, tightened, counter-tightened, and then tightened again. All the mounted implants were left in the same environment for 3 hours, and the reverse tightening values were then measured. RESULTS: The mean reverse tightening values of the first 4 groups ranged from 21.49 Ncm to 22.57 Ncm, whereas the reverse tightening value for the fifth group was 25.51 Ncm. A significant difference was found among the groups (P<.05) with reverse tightening data. CONCLUSIONS: No significant difference was found in tightening the abutment screw 2 times with a 10-minute interval time, no interval time, or tightening it 1 time only. However, a significant difference was found in reverse tightening in the 3-time tightening and counter-tightening group.

Validating implant torque limiting devices with a custom tool: A dental technique.

The dental torque limiting device is a tool used to deliver a measured torque to implants and to their associated components. The torque delivery must be accurate and precise, especially when considering screw joints. Similar torque wrenches are used in various industries, and recommendations on calibration are provided by the International Organization for Standardization 6789-2:2017. It states that hand torque tools should be calibrated annually or more frequently if subjected to extreme temperature conditions such as steam sterilization. The International Organization for Standardization standard recommends that calibration may be performed by direct comparison of 2 torque devices provided that 1 is known to be within calibration. This technique article describes the procedures for fabricating a tool that couples 2 dental torque limiting devices. It may be used for calibrating and validating both electrical and mechanical torque limiting devices.

Protecting critical connection sites of a custom cast abutment with a protector cap during fabrication.

Custom castable abutments with metal bases can be waxed and cast. However, the devesting stage may damage the milled metal base when airborne-particle abrasion is used. This may affect the abutment-to-implant joint, as well as the screw seat. Either of these can result in an improper connection that may produce a negative effect on joint performance. This technique describes the use of a computer-aided design and computer-aided manufactured zirconia protector cap and peg, placed before investing, that shield against airborne-particle damage during devesting.

The effect of screwdriver angle variation on the off-axis implant abutment system and hexalobular screw.

STATEMENT OF PROBLEM: A recently introduced hexalobular screw system allows for off-axial screw channel access. The screwdriver angle input torque relative to the screw axis output torque has not been established. PURPOSE: The purpose of this in vitro study was to evaluate the effect of maximum angulation on the abutment-implant screw connection and torque values for a hexalobular screw system and to determine how input versus output varies with the angle of the screwdriver. MATERIAL AND METHODS: Twenty angulated abutments attached to implant fixtures were tightened to the manufacturers' prescribed torque at 2 different input angles: 0 and 28 degrees off axial (n=10/group). Input and reverse torque values were recorded by using calibrated torque sensor devices and compared for significant differences by using the Mann-Whitney U test. Fifty hexalobular screws were subjected to screwdriver angle variations of 0, 10, 15, 25, and 28 degrees (n=10/group). The input torque (screw head) and output torque (screw body) were recorded. The Kruskal-Wallis rank sum test and the post hoc Dunn test were used for statistical analysis of the output torque (α=.05). RESULTS: Significant differences in mean reverse torque existed (P<.05) between the abutment-implant connection at the 2 angles measured. Significant differences were found at the output torque with varying angles of input torque (P<.05). No statistically significant differences were determined between 0 and 15 degrees. Torque values were significantly reduced for 25- and 28-degree angulations. CONCLUSIONS: Angle changes may affect the screw torque and ultimate preload. At extreme angulation beyond 15 degrees, screw performance may be affected and have clinical relevance in areas with high occlusal load.

Testing and calibrating the mechanical-type toggle torque wrenches used in implant dentistry: A dental technique.

Abutment screw loosening is still the most common complication reported with implant-supported crowns. One factor that contributes to screw loosening is not achieving the proper torque during the tightening process. Torque application and measurement is usually achieved by using one of the available types of mechanical torque wrench. Of these, the toggle wrench has been shown to produce erroneous readings, and regular testing is recommended. If it is inaccurate, it must be recalibrated or replaced. Calibration typically requires specialized instruments unavailable to most clinicians, so the device must be sent away. This article describes a straightforward, in-office, and inexpensive alternative for testing and recalibrating a toggle torque wrench.

An in vitro investigation comparing methods of minimizing excess luting agent for cement-retained implant-supported fixed partial dentures.

STATEMENT OF PROBLEM: The use of cement-retained implant-supported prostheses is a well-established treatment option. Techniques have been proposed to reduce the amount of residual excess cement (REC) around cement-retained single-implant restorations. However, studies evaluating the effectiveness of such techniques related to cement-retained implant-supported fixed partial dentures (CRISFPDs) are lacking. PURPOSE: The purpose of this in vitro study was to evaluate the effectiveness of various cement application techniques for CRISFPDs. MATERIAL AND METHODS: Two implant analogs were placed in the lateral incisor sites in a maxillary, 3D printed cast with 4 missing incisors. Twenty standardized, removable, printed soft-tissue replicas, 40 milled titanium custom abutments, and 20 milled zirconia CRISFPDs were fabricated. Two cement application techniques, the brush on technique (BOT), and the polyvinyl siloxane index (PI) technique were compared. Two cementation techniques, without bib (control) (n=10) and with a polytetrafluoroethylene (PTFE) bib (test) (n=10), were used. A premeasured amount of interim cement was used to cement the CRISFPDs. The CRISFPDs were retrieved after cementation, and standardized photographs of 4 quadrants of each abutment-CRISFPD assembly were made by using a software program that is used to calculate the ratio between the area covered with REC and the total specimen area. The extension of the REC on both the abutment and soft-tissue replica was measured at sites before and after cleaning the REC. A generalized linear mixed-model procedure was used for statistical analysis (α=.05). RESULTS: For cement application, the polyvinyl siloxane (PVS) index technique had significantly less REC than the brush on technique (P<.05). The use of a PTFE bib led to significantly less REC than when no bib was used (P<.05). CONCLUSIONS: The use of the PVS index technique along with a PTFE bib was effective in reducing REC for CRISFPDs.

A technique to validate the accuracy of a beam-type mechanical torque limiting device.

Tightening torques are often specified in implant dentistry, including for surgical procedures, testing implant stability, and attaching prosthetic components when screws are used. The mechanical torque limiting devices (MTLDs) commonly used are typically either a toggle-type or beam-type. The International Organization for Standardization (ISO) 6789 recommends MTLDs should be periodically tested to confirm the validity of their readings, and, where necessary, recalibrated if possible or replaced. The verification of the toggle-type MLTD has been previously published. This article describes a straightforward, in-office technique to verify a beam-type MTLD.

Clinician preferences for complete-arch fixed implant-supported prostheses: A survey of the membership of the Pacific Coast Society for Prosthodontics.

STATEMENT OF PROBLEM: Current in vivo and in vitro research has difficulty keeping pace with the rapid evolution of materials, protocols, and designs of the complete-arch fixed implant-supported prosthesis. PURPOSE: The purpose of this survey was to determine the current prevalence of usage of various treatment modalities and materials for complete-arch fixed implant-supported prostheses. MATERIAL AND METHODS: From November to December of 2018, a survey invitation was sent out to members of the Pacific Coast Society for Prosthodontics (PCSP). The survey was hosted online, and asked a series of 18 questions related to the materials, protocols, and design preferences for complete-arch fixed implant-supported prostheses. The prompt included the suggestion that answers should be based on preferences for ideal treatment of a hypothetical completely edentulous patient seeking fixed, implant-supported prostheses, assuming sufficient native bone and an opposing complete-arch fixed implant-supported prosthesis. RESULTS: Of 133 invitations sent via email, 45 (34%) surveys were started and 48 (36%) were completed. Pertinent results are summarized in histograms with color coding in each answer group to indicate the total number of arches the person had treated (a proxy for experience). Most respondents were in private practice (73%) and had completed more than 21 arches of fixed implant-supported prostheses (62%). Nearly half (49%) of the respondents preferred 6 implants in the maxilla, while the preferred number in the mandible was highly varied between 4 (33%), 5 (27%), and 6 (29%) implants. Three-fourths (75%) preferred bone-level implant designs, and the plurality was ambivalent on the use of a platform-switched design (48%). Two-thirds (67%) preferred to deliver a complete-arch fixed provisional prosthesis at the time of surgery. Two-thirds (67%) preferred to make the definitive impression by using rigidly splinted, open-tray copings. While most (67%) preferred to fabricate the definitive maxillary and mandibular prostheses with identical occlusal materials, the specifics of material selection between arches varied greatly. In the maxilla, a plurality preferred anatomic contour zirconia with titanium bases (33%). In the mandible, a plurality preferred laboratory-processed resin with denture teeth over a milled metal bar (32%). CONCLUSIONS: While a wide range of protocols, designs, and materials exist in the use of the complete-arch fixed implant-supported prosthesis, these results provide a snapshot of current clinical preferences in the Western United States.

Effect of image sharpening on radiographic image quality.

STATEMENT OF PROBLEM: The image sharpening algorithm, unsharp masking (USM), may cause artifacts that reduce the diagnostic value of digital images. It may create overshoot artifacts that can be misdiagnosed as pathosis or prosthesis misfit. The effect of this image sharpening and the extent of overshoot artifacts on image quality requires investigation. PURPOSE: The purpose of this in vitro study was to evaluate the effect of USM on digital dental radiographic quality and to demonstrate the extent of overshoot artifacts. MATERIAL AND METHODS: Three digital sensors (2 complementary metal-oxide-semiconductors and 1 photostimulable phosphor) were exposed using a digital dental quality assurance imaging phantom to evaluate contrast resolution, spatial resolution, and dynamic range. The 3 sensors were again exposed without the phantom to determine the degree of radiographic noise. Each image was sharpened and then highly sharpened. Overshoot was measured, and images were compared using the Friedman 2-way ANOVA analysis. RESULTS: Image sharpening significantly affected spatial resolution and noise. Conversely, dynamic range and contrast resolution were not significantly affected by image sharpening. Overshoot artifacts increased with image sharpening. CONCLUSIONS: Image sharpening improves visual image quality but significantly increases overshoot artifacts that adversely affect radiographic diagnosis. Data from this study indicate that image sharpening causes artifacts that could negatively affect accurate diagnosis.

Colorizing titanium-6aluminum-4vanadium alloy using electrochemical anodization: Developing a color chart.

Colorizing titanium alloys by electrochemical anodization is used in dentistry especially for identification purposes. Colorization is the result of distinct voltage applications to specific titanium alloys when placed in an electrolyte. Titanium and titanium alloys differ in their ability to be anodized. As titanium-6aluminum-4vanadium is commonly used as an abutment material, we have developed a specific color reference scale relating color to the voltage applied.

Development and capture of soft tissue contours at time of implant placement.

A technique is described which will generate a customized healing abutment for a dental implant to allow the development of ideal soft tissue contours. With implant position and soft tissue contours defined at surgery, customized impression techniques can be used to capture those details and help generate the definitive implant-supported restoration. This workflow reduces the number of patient visits.

In vitro effects of dental cements on hard and soft tissues associated with dental implants.

STATEMENT OF PROBLEM: Dental cements for cement-retained restorations are often chosen based on clinician preference for the product's material properties, mixing process, delivery mechanism, or viscosity. The composition of dental cement may play a significant role in the proliferation or inhibition of different bacterial strains associated with peri-implant disease, and the effect of dental cements on host cellular proliferation may provide further insight into appropriate cement material selection. PURPOSE: The purpose of this in vitro study was to investigate the cellular host response of bone cells (osteoblasts) and soft tissue cells (gingival fibroblasts) to dental cements. MATERIAL AND METHODS: Zinc oxide (eugenol and noneugenol), zinc phosphate, and acrylic resin cements were molded into pellets and directly applied to confluent preosteoblast (cell line MC3T3 E1) or gingival fibroblast cell cultures (cell line HGF) to determine cellular viability after exposure. Controls were defined as confluent cell cultures with no cement exposure. Direct contact cell culture testing was conducted following International Organization for Standardization 10993 methods, and all experiments were performed in triplicate. To compare either the MC3T3 E1 cell line, or the HGF cell line alone, a 1-way ANOVA test with multiple comparisons was used (α=.05). To compare the MC3T3 E1 cell line results and the HGF cell line results, a 2-way ANOVA test with multiple comparisons was used (α=.05). RESULTS: The results of this study illustrated that while both bone and soft tissue cell lines were vulnerable to the dental cement test materials, the soft tissue cell line (human gingival fibroblasts) was more susceptible to reduced cellular viability after exposure. The HGF cell line was much more sensitive to cement exposure. Here, the acrylic resin, zinc oxide (eugenol), and zinc phosphate cements significantly reduced cellular viability after exposure with respect to HGF cells only. CONCLUSIONS: Within the limitation of this in vitro cellular study, the results indicated that cell response to various implant cements varied significantly, with osteoblast proliferation much less affected than gingival fibroblast cells. Furthermore, the zinc oxide noneugenol dental cement appeared to affect the cell lines significantly less than the other test cements.

In-office technique for selectively etching titanium abutments to improve bonding for interim implant prostheses.

A technique is described for increasing the surface area of a titanium abutment with hydrofluoric acid etching. This provides mechanical retention for acrylic resin and composite resins and can be easily and rapidly accomplished in both the laboratory and clinic.

Effect of surface treatments on titanium alloy bonding to lithium disilicate glass-ceramics.

STATEMENT OF PROBLEM: The esthetic challenges of using all-titanium alloy abutments have led to the increasing use of prefabricated titanium inserts bonded to tooth-colored abutments and fixed dental prostheses. Optimal bonding protocols related to the titanium alloy treatment have not been established. PURPOSE: The purpose of this in vitro study was to evaluate the effects of different surface treatments and cementation procedure combinations of titanium-6aluminum-4vanadium alloy (Ti6Al4V) disks on the bond strength of lithium disilicate glass-ceramics. MATERIAL AND METHODS: A total of 100 computer-aided designed and computer-aided manufacturing (CAD-CAM) Ti6Al4V disks (4×6.6 mm) were used. As-milled specimens, without surface treatment, were used as controls. Surface treatment variables including alumina airborne-particle abrasion (50 µm, 0.4 MPa, 10 seconds, at 20-mm distance), ceramic etchant gels (5% and 9.5%), and buffered hydrofluoric (HF) acid etching, and etching times (30 and 90 seconds) were assessed. Heat-pressed lithium disilicate disks were fabricated and bonded with resin cements onto the treated surfaces (10 groups; n=10/group) according to the manufacturers' instructions. After 5000 cycles of thermal cycling, a shear bond strength test was conducted using a universal testing machine and a customized fixture with crosshead speed of 5 mm/min. ANOVA and Tukey honest significant differences tests were used for statistical analysis (α=.05). Representative specimens were observed using stereomicroscopy and scanning electron microscopy to determine the surface patterns after different treatments. RESULTS: The mean ±SD bond strength values ranged from 13.1 ±6.9 MPa to 53.0 ±9.7 MPa. Statistically significant higher shear bond strength values were obtained using airborne-particle abrasion alone or etching with 9.5% HF for 30 seconds without airborne-particle abrasion (P<.05). Resin cements tested in this study had a similar effect on the bonding strength values (P>.05). CONCLUSIONS: Individual treatments with alumina airborne-particle abrasion alone or etching with 95% HF for 30 seconds improved shear bond strength. However, combining alumina airborne-particle abrasion with different HF etching procedures did not.