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 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.

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.

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.

How Can Clinicians Limit the Risk of Peri-implantitis?

When using dental implants as a treatment modality for tooth replacement, the integration of peri-implant soft tissue is an extremely important consideration. Numerous systemic risk factors for peri-implant disease are known to be associated with peri-implant soft tissues. The soft-tissue connection provides a barrier seal directly to the implant or implant abutment and plays a critical role in limiting peri-implant disease. Therefore, clinicicans must take great care in managing the soft tissue. This article discusses three key stages of soft-tissue connection that should be considered when providing dental implant therapy: the healing stage, where cellular adhesion and proliferation are attained; the restorative phase, during which protection is provided to the mature soft-tissue site; and maintenance, a phase where the soft tissue offers revealing information about the health of the implant.

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.

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.

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.

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.

Techniques to Optimize Color Esthetics, Bonding, and Peri-implant Tissue Health With Titanium Implant Abutments.

Due to their exceptional biological and mechanical properties, titanium and its alloys are commonly used in both dental implants and implant abutments, upon which prostheses can be attached. The gray color of titanium metal, however, can elicit esthetic problems, as it has the potential to show through a translucent ceramic restorative material. Various solutions have been proposed and used to attempt to overcome esthetic issues associated with titanium. This article describes a simple, economical technique to color titanium abutments and components utilizing anodization, resulting in light reflection and color enhancement through a natural physics phenomenon known as light interference patterns. A technique for improving the bonding capabilities of cement to the abutment is also discussed.

Laboratory technique for coloring titanium abutments to improve esthetics.

Titanium alloys are used for implant abutments onto which prostheses are attached. One major disadvantage of titanium abutments is their esthetics; the metallic gray color may show through the restorative material or through surrounding tissues. A laboratory technique using readily available household items is described that can alter the abutment color by anodization.

Characterization of Cement Particles Found in Peri-implantitis-Affected Human Biopsy Specimens.

PURPOSE: Peri-implantitis is a disease characterized by soft tissue inflammation and continued loss of supporting bone, which can result in implant failure. Peri-implantitis is a multifactorial disease, and one of its triggering factors may be the presence of excess cement in the soft tissues surrounding an implant. This descriptive study evaluated the composition of foreign particles from 36 human biopsy specimens with 19 specimens selected for analysis. The biopsy specimens were obtained from soft tissues affected by peri-implantitis around cement-retained implant crowns and compared with the elemental composition of commercial luting cement. MATERIALS AND METHODS: Nineteen biopsy specimens were chosen for the comparison, and five test cements (TempBond, Telio, Premier Implant Cement, Intermediate Restorative Material, and Relyx) were analyzed using scanning electron microscopy equipped with energy dispersive x-ray spectroscopy. This enabled the identification of the chemical composition of foreign particles embedded in the tissue specimens and the composition of the five cements. Statistical analysis was conducted using classification trees to pair the particles present in each specimen with the known cements. RESULTS: The particles in each biopsy specimen could be associated with one of the commercial cements with a level of probability ranging between .79 and 1. TempBond particles were found in one biopsy specimen, Telio particles in seven, Premier Implant Cement particles in four, Relyx particles in four, and Intermediate Restorative Material particles in three. CONCLUSION: Particles found in human soft tissue biopsy specimens around implants affected by peri-implant disease were associated with five commercially available dental cements.

The Interaction of Implant Luting Cements and Oral Bacteria Linked to Peri-Implant Disease: An In Vitro Analysis of Planktonic and Biofilm Growth--A Preliminary Study.

BACKGROUND: There is little consensus on the most appropriate cement to use when restoring a cement-retained, implant-supported restoration. One consideration should be the interaction of pathogenic oral bacteria with restorative cements. PURPOSE: To determine how oral bacteria associated with peri-implant disease grow in the presence of implant cements. MATERIALS AND METHODS: Five test cements with varying composition (zinc oxide-eugenol [TBO], eugenol-free zinc oxide [TBNE], zinc orthophosphate [FL], and two resin cements [PIC and ML]) were used to fabricate specimen disks. The disks were submerged in bacterial suspensions of either Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, or Porphyromonas gingivalis. Planktonic bacterial growth within the test media was measured by determining the optical density of the cultures (OD600 ). Positive controls (media and bacteria without cement disks) and negative controls (media alone) were similarly evaluated. The mean and standard deviations (SD) were calculated for planktonic growth from three separate experiments. ANOVA statistical analysis with post hoc Tukey tests was performed where differences existed (p < .05). Selected cement disks (TBO and ML) were further examined for bacterial biofilm growth. Surface bacteria were removed and grown on agar media, and colony-forming units (CFUs) were quantified. RESULTS: Planktonic growth for both A. actinomycetemcomitans and P. gingivalis was significantly inhibited (p < .05) when grown in the presence of cement disks consisting of TBNE, PIC, FL, and TBO. In contrast, neither of these bacteria displayed growth inhibition in the presence of ML cement disks. F. nucleatum growth was also significantly inhibited by PIC, FL. and TBO (p < .05), but not by ML and TBNE cement disks. CFU counts for the biofilm study for TBO gave minimal and, in some instances, no bacterial adherence and growth, in contrast to ML, which supported substantially greater bacterial biofilm growth. CONCLUSION: Cements display differing abilities to inhibit both planktonic and biofilm bacterial growth. Cements with the ability to reduce planktonic or biofilm growth of the test bacteria may be advantageous in reducing peri-implant disease. Understanding the microbial growth-inhibiting characteristics of different cement types should be considered important in the selection criteria.

Assessing fit at the implant-abutment junction with a radiographic device that does not require access to the implant body.

STATEMENT OF PROBLEM: Radiograph paralleling devices provide an excellent means of obtaining orthogonal radiographs for the evaluation of the fit of implant restorations. Unfortunately, the clinical applicability of such devices is a significant issue because access to the implant body must be obtained at each radiographic appointment. PURPOSE: The purpose of the study was to investigate whether the fit or microgap at the implant-abutment junction could be more accurately and confidently assessed with a novel radiograph paralleling device that did not require access to the implant body once a proper registration index was made. MATERIAL AND METHODS: Microgaps of 0, 50, and 100 µm were introduced at the implant-abutment junction of a provisional implant crown in a manikin-typodont assembly. Dental assistants made 54 radiographs (18 per microgap) of the crown with and without a radiograph paralleling device; 9 clinicians then evaluated the standardized radiographs for the presence of misfit. The Cochran-Mantel-Haenszel test and the corresponding odds ratios were used to evaluate the effectiveness of the paralleling device in helping clinicians better assess misfit from the radiographs made. RESULTS: The use of the device led to a higher percentage of accuracy under all conditions (79.0% vs 70.4% at the 0-µm gap, 77.8% vs 16.1% at the 50-µm gap, and 100% vs 92.6% at the 100-µm gap); the improvement was statistically significant at the 50-µm gap (P<.001) and 100-µm gap (P=.049) but not at the 0-µm gap (P=.364). The odds ratio (95% confidence interval) of obtaining correct versus wrong answers with the device compared with without the device was 18.64 (7.94-43.77) at the 50-µm gap and 5.40 (0.25-114.25) at the 100-µm gap. CONCLUSIONS: The study indicated that the paralleling device helped the clinician more accurately assess the implant-abutment junction with the 50- and 100-µm gaps.

A radiograph positioning technique to evaluate prosthetic misfit and bone loss around implants.

A radiograph positioning device was developed to fit with commercially available film holders and implant systems. The device is indexed to the dental implant body and the adjacent dentition by using an implant placement driver and polyvinyl siloxane occlusal registration material. By fitting the device to a conventional film holder, accurate orthogonal radiographs can monitor changes in bone architecture and prosthetic misfit.