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Statement of Problem: Fractured prosthetic implant screws cannot be removed in all patients, ultimately leading to the removal of the implant. Whether an intentionally shortened prosthetic implant screw (SPIS) can provide adequate retention is unclear., Purpose: The purpose of this in vitro study was to evaluate the resistance to loosening of SPISs engaging the remaining coronal internal threads as a possible solution to maintaining both implant and restoration., Material and Methods: Fifty grade V titanium SPISs were used to tighten 50 titanium transepithelial abutments on implants to 30 Ncm. The specimens were distributed into 5 groups (n=10) according to the conditions under which the screws were secured to manufacturer-recommended preload: dry (D), moistened in saliva (AS), moistened in chlorhexidine (CLHX), wrapped in polytetrafluoroethylene tape (PTFE), and resin cemented (RE). All groups were subjected to a cyclic loading test (240 000 cycles). The reverse torque value (RTV) of the SPIS was registered twice: 24 hours after initial tightening (T1); and after retightening and the cyclic loading test (T2). The resultant RTV was compared with the 30-Ncm tightening torque to assess torque loosening. The Kruskal-Wallis and Mann-Whitney tests were used for the comparisons between groups and the Wilcoxon test for the intragroup comparisons (α=.05 with Bonferroni correction)., Results: At T1, all groups found lower mean±standard deviation RTVs than the reference tightening torque (30 Ncm) (D 24.82±2.34 Ncm, AS 25.56±2.89 Ncm, PTFE 26.02±2.26 Ncm, CLHX 26.26±1.82 Ncm), except the resin-cemented group, which increased its RTV (RE 44.01±19.94 Ncm). At T2, all the groups found lower RTVs than the reference tightening torque, and the torque values at T1 (D 19.81±6.59 Ncm, CLHX 18.98±6.36 Ncm, AS 21.28±7.32 Ncm), with the exception of PTFE (24.07±3.41 Ncm) and RE (41.47±21.68 Ncm), where RTV was similar to that recorded at T1. At T1, significant differences were found among the groups (P=.024). At T2, after cyclic loading, the RE group found the highest RTV, reporting significant differences with the D and CHLX groups (P<.05) and statistically similar to the AS group (P=.068)., Conclusions: PTFE-wrapped screws found similar RTVs after the fatigue test than dry, moistened with saliva, and moistened with chlorhexidine screws. Resin-cemented shortened prosthetic implant screws were found to be the most resistant to loosening after cyclic loading., (Copyright © 2024 Editorial Council for The Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Implant-supported fixed dental prostheses have been classified into screw-retained and cement-retained types, and each retaining type has complications. A novel retentive cementless double crown (CLD) type of the implant-supported fixed prosthesis has been developed. CLD has air pockets in the intaglio surface of the crown and does not require cement or a screw hole. However, studies on the retention force and stress distribution of the system are lacking., Purpose: The purpose of this in vitro study was to evaluate the retention force and stress distribution in the CLD system., Material and Methods: The specimen comprised an implant, a titanium abutment, and a zirconia crown. Retention forces of 10 specimens of the CLD type were measured at no loading and after cyclic loading for 50, 100, 200, 600, 10 000, and 1 000 000 cycles by using a universal testing machine with a custom attachment device. Forty specimens of the stress distribution test were divided into 4 groups based on the retention type (cement-retained or CLD type) and load direction (vertical or oblique). Strain gauges were attached onto the buccal and lingual sides of the implant, and microstrain values were measured. One-way analysis of variance with the post hoc Tukey honestly significant difference test was performed on the retention force data, and the t test was performed to analyze the microstrain value data (α=.05)., Results: Retention forces after 0, 50, 100, 200, 600, 10 000, and 1 000 000 load cycles were 18.12 ±6.16 N, 20.47 ±5.78 N, 19.79 ±6.61 N, 18.46 ±5.23 N, 19.60 ±6.93 N, 21.75 ±5.03 N, and 40.91 ±9.32 N, respectively, and after 1 000 000 cycles, the retention force was significantly higher than that of other load cycles (P<.05). The mean of maximum microstrain values under the vertical load were similar in the cement-retained type (buccal side, 834.96 ±53.69 μm/m; lingual side, 490.76 ±34.12 μm/m) and the CLD type (buccal side, 814.28 ±71.20 μm/m; lingual side, 479.10 ±30.74) (P>.05), and the mean of maximum microstrain values under the oblique load was also similar in the cement-retained type (buccal side, 1991.04 ±109.89 μm/m; lingual side, -2232.41 ±189.88) and the CLD type (buccal side, 1932.47 ±152.51 μm/m; lingual side, -2097.47 ±130.69 μm/m) (P>.05)., Conclusions: The CLD type had clinically acceptable retention during 1 000 000 load cycles and had a similar or better stress distribution capability than the cement-retained type., (Copyright © 2020 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

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., (Copyright © 2019 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Removing cement-retained implant-supported prostheses may be challenging for clinicians. A method combining a cone beam computed tomography (CBCT) and a digital scan with a virtual surgical planning software program is described to identify the perforation site of a cement-retained implant-supported prosthesis to locate the abutment screw., (Copyright © 2020 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Automixing and dispensing cements is a straightforward approach with consistent dosing. Previous studies have demonstrated clinically significant differences in crown retention between power-liquid and paste-paste forms of the same cement, as the composition between the 2 differs. A self-adhesive modified-resin (SAMR) and a resin-modified glass ionomer (RMGI) cement, originally offered as a powder-liquid, are now in common use as paste-paste automixed cements. With the increased use of zirconia restorations, the long-term retention of zirconia crowns for these 2 automixed cements should be evaluated., Purpose: The purpose of this in vitro study was to determine whether zirconia crowns cemented with 2 automixed cements provided clinically acceptable retention after 6 months of aging with monthly thermocycling., Material and Methods: Extracted molars were mounted in resin and prepared with a flat occlusal surface, 20-degree taper, approximately 4-mm axial length, and with the axio-occlusal line angle slightly rounded. Prepared teeth were equally distributed into 3 cementation groups (n=12) to achieve nearly equal mean preparation surface areas for each group. Zirconia crowns (IPS ZirCAD LT) were fabricated with an added occlusal bar to facilitate removal of the cemented crowns. Cement space was set at 45 μm axially and 55 μm occlusally. After sintering and before delivery, the intaglio surfaces were airborne-particle abraded with 50-μm alumina at 275-kPa pressure for 3 seconds and then steam cleaned. Cements were the original powder-liquid RelyX Luting (RMGI; RXL) as the control, paste-paste, automixed systems RelyX Luting Plus Automix (RMGI; RXLA), and RelyX Unicem 2 Automix (SAMR; RXUA). Crowns were cemented under 196 N force, placed in an oven at 37 °C and 100% humidity during setting and then thermocycled (5 °C-55 °C) for 5000 cycles monthly for 6 months. The crowns were removed axially with a universal testing machine at 0.5 mm/min. Removal forces were recorded and dislodgement stress calculated by using the surface area of each preparation. One-way ANOVA was used for dislodgement stress and force. Chi-square test was used for cement location after testing (α=.05)., Results: RXLA demonstrated considerably lower crown retention (1.3 MPa) and differed significantly (P<.001) from RXUA (3.1 MPa) and RXL (3.1 MPa). Modes of failure showed most of the cement remaining only in the crown intaglio for RXLA for all specimens, whereas half of the crowns for RXL and RXUA demonstrated cement adhesion to both dentin and the intaglio surface, indicating cohesive failure of the cement at separation. As the Levene test was significant, the Games-Howell test was used for mean differences. The χ 2 analysis was significant., Conclusions: After long-term aging with monthly thermocycling, high-strength zirconia crowns were strongly retained by 2 (RXL, RXUA) of the 3 cements. Crown retention for RelyX Luting Plus Automix was less than half in comparison and with cement found only on the intaglio surface after separation., (Copyright © 2020 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Implant-supported prostheses have typically been retained by cement or screws, each of which has advantages and disadvantages. Two new types of prosthesis with complementary advantages and disadvantages have been proposed: the screw- and cement-retained prosthesis, which combines cement and screw retention, and the antiloosening inner-post screw (ALIPS) type, which uses lateral screws. Both esthetic and functional factors should be considered for anterior prostheses; however, clinical studies of the complication rates of these designs are lacking., Purpose: The purpose of this retrospective clinical study was to evaluate the complications of dental implant-supported restorations with various prosthetic types in the anterior region and to analyze other factors that affect complications., Material and Methods: This study included 51 patients who had 83 implants placed in the anterior region by a single clinician between August 2009 and December 2016. Surgical and prosthetic features were recorded, and implant complications were analyzed., Results: There were 45 (55.4%) cement-retained implants, 5 (6.0%) screw- and cement-retained prosthesis implants, and 32 (38.6%) ALIPS-retained implants. Peri-implant mucositis was observed most frequently in the ALIPS type (21.9%), but the biological complications did not differ significantly with the prosthetic type. The most common mechanical complication was loss of retention in the cement type of prosthesis (30.4%) and screw loosening in the ALIPS type (43.8%). Implant complications varied with position (maxilla or mandible) and implantation timing (period from tooth extraction to implant placement)., Conclusions: The complications of implants placed in the anterior region were affected by different factors but did not differ significantly with the type of the retention., (Copyright © 2020 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: A nitinol sleeve that uses shape memory to rapidly unlock dental restorations from implant abutments has been developed to allow prosthesis removal for assessment and maintenance, and clinical treatment has been promising. However, objective studies that evaluate the wear and retention performance after short-term clinical use are lacking., Purpose: The purpose of this clinical study was to evaluate the wear and retention performance of a shape-memory abutment system after 6 months of clinical use., Material and Methods: Shape-memory alloy sleeves on posterior osseointegrated implants were retrieved after 6 months of clinical use. Scanning electron microscopy (SEM) was used to evaluate the surfaces of the retention sleeve's arms for wear. Uniaxial tensile testing was performed to measure the change in retention force after clinical use. Average retention values of the shape-memory abutment system were compared with previously reported in vitro retention values for definitive and interim cements used in titanium abutment and coping assemblies by using the Welch t test., Results: No evidence of wear, fracture, or chipping was observed during SEM analysis on the shape-memory alloy sleeves. Additionally, no statistically significant difference was found in the median retention force for new (484.5 N) and clinically retrieved (476 N) nitinol sleeve specimens. Compared with a commercially available resin cement, the mean retention force for the control sleeves (480 ±37 N) was higher than that for the freshly cemented specimens (336.3 ±188 N). After 5000 cycles of compressive loads, the mean retention force for cement specimens decreased (209.4 ±83 N), while the clinical sleeves (476 ±50 N) remained unchanged., Conclusions: According to the results of this study, after 6 months of clinical use, the engaging surfaces of the shape-memory alloy sleeve did not show signs of wear, and the retention force was unchanged., (Copyright © 2019 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Residual cement is detrimental to the long-term success of dental implants with a cement-retained restoration. The complete elimination of excess cement remains a challenge., Purpose: The purpose of this in vitro study was to evaluate the effects of precementation technique on minimizing the residual cement and retention of restorations., Material and Methods: Four custom cobalt-chromium alloy (Co-Cr) abutments were manufactured by computer-aided design and computer-aided manufacturing (CAD-CAM) as precementation abutments with height and radius reductions of 25 μm (A25), 50 μm (A50), 75 μm (A75), and 100 μm (A100). Fifty CAD-CAM-fabricated standard Co-Cr abutments and corresponding crowns were randomly matched and treated as follows: 10 specimens were cemented with the conventional cementation procedure with glass ionomer cement (G0), and 40 were precemented with precementation abutments (n=10) before the definitive cementation with standard abutments (G25, G50, G75, G100). The weight of the cement in the cement space was calculated, and the marginal sealing was evaluated by using a stereoscopic microscope. The effects of precementation with resin cement on minimizing residual cement around the marginal area of dental implants were further evaluated extraorally. The influence of precementation with glass ionomer and resin cement on the retention force was analyzed by using a universal testing machine at a crosshead speed of 0.5 mm/min. One-way ANOVA was used to analyze cement mass and marginal sealing values. Two-way ANOVA was used to compare the retention forces (α=.05)., Results: The cement weight of G50 (7.2 ±0.6 mg) was significantly higher than that of G25 (6.0 ±1.1 mg, P<.05), while no significant differences in cement weights were found among G50, G75, and G100. Consistently, the G50, G75, and G100 had higher marginal sealing values than that of the G25 (P<.01). Extraoral experiments showed that the precementation with A50 reduced subgingival residual cement without affecting retention., Conclusions: These in vitro results suggest that precementation with a precisely manufactured precementation abutment minimized the residual cement around implant abutments, and 50 μm could be a preferable precementation space., (Copyright © 2019 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: After implant rehabilitation, clinicians may need to remove a restoration because of technical and biological complications. For cement-retained implant-supported prostheses (ISPs), the retrievability process may damage the components of the prosthesis, the intaglio surface of the implant, or the abutment screw. To avoid that, the screw access hole (SAH) of the dental implant abutment (DIA) should be registered. Although several clinical reports and dental techniques have been proposed, a review of existing techniques is lacking., Purpose: The purpose of this scoping review was to evaluate the different techniques described for retrievability and for registering the SAH of cement-retained ISPs., Material and Methods: An electronic search of English language dental literature in the PubMed, Scopus, Google Scholar, and SciELO databases was conducted from 1980 to December 2017 with appropriate keywords and phrases. A hand search of relevant dental journals was also completed, and exclusion criteria were applied after full-text evaluation., Results: The electronic and hand search revealed 325 articles. However, 252 publications were discarded after duplicates were removed. After reading the title and abstracts, 15 studies were excluded, and the full text of 64 publications was screened for inclusion and exclusion criteria. Forty studies were selected and included for final evaluation. The evaluation revealed 6 techniques for retrievability and 9 techniques for registering the position of the SAH, divided into 2-dimensional (2D) and 3-dimensional (3D) techniques., Conclusions: Cement-retained ISPs can be effectively retrieved by using interim cements and possibly by using a combined cement- and screw-retained design. Vacuum guides with guiding sleeves and computer-aided design and computer-aided manufacturing (CAD-CAM) guide templates are possible effective 3D techniques for registering the screw access channel (SAC) location and angulation., (Copyright © 2019 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Screw- and cement-based retention mechanisms are used to attach prostheses to dental implants; however, each approach can lead to clinical complications such as crown fracturing or peri-implantitis. A novel abutment and prosthesis retention system has been engineered to achieve the esthetics and retention force of cement-based fixation while maintaining the retrievability of screw-retained restorations., Purpose: The purpose of this pilot clinical study was to evaluate the effectiveness of this innovative retention system on posterior tooth restorations., Material and Methods: This clinical study, with up to 6 months of follow-up, included 8 participants with posterior osseointegrated implants who met the eligibility criteria to receive the abutment and shape memory sleeve. Radiographs were used to evaluate crown seating. Crown stability was measured using the Periotest, and occlusal analysis was performed using the Tekscan system and shimstock. Peri-implant health was evaluated by probing, and the plaque and gingival indices were recorded. In addition, patient-reported outcomes were recorded., Results: Minimal differences were observed between baseline and endpoint assessment of the plaque and gingival indices, probing depth, and proximal and occlusal contacts. There were no patient-reported problems or complaints about discomfort. The overall peri-implant health remained unchanged from the baseline evaluations for all participants. Proximal contact around the restoration was present at the baseline and at the conclusion of the study for 7 of the participants. Occlusal contact was observed to be either light (5 participants) or holding (3 participants). In addition, visual inspection of retrieved crowns revealed clean surfaces free of macroparticle ingress, and bacterial accumulation at the coping-abutment interface was not detected., Conclusions: The safety and efficacy findings of this pilot clinical study suggest that this new shape memory alloy-based retention system may provide a suitable alternative for implant prosthodontics. The retention system allowed for easy prosthesis seating and retrieval., (Copyright © 2019 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

A microlocking implant prosthetic system has recently been developed to address the limitations of conventional screw- and cement-retained implant-supported fixed dental prostheses. This prosthesis system consists of a precision-machined abutment and an attachment that includes zirconia balls and a nickel-titanium spring, thus providing retrievability and constant retention of the prosthesis. In addition, screw-related complications are avoided because there is no retention screw. The occlusal access hole is of a smaller diameter than that of conventional screw-retained prostheses, which is beneficial for esthetics and occlusion. It also prevents common complications of cement-retained prostheses because residual cement around the prosthesis can be removed extraorally. This article presents a clinical treatment with this new prosthetic system., (Copyright © 2019 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Limited information is available on the effect of LOCATOR abutment length and luting cement type on retention to intraradicular dentin in overdentures., Purpose: The purpose of this in vitro study was to evaluate the effect of the length of a commercially available LOCATOR abutment and cement type on retention in the root canal., Material and Methods: Eighty LOCATOR abutments with a standard length of 6 mm were obtained. Half of them were shortened to 3 mm. Eighty recently extracted single-rooted teeth were divided into 2 groups. The post space was prepared to 6 mm in the first group and 3 mm in the second. After preparation, the LOCATOR abutments were luted with one of the following cements: dual-polymerized glass-reinforced resin cement (Parapost Paracore), dual-polymerized resin cement (Variolink II), self-adhesive resin cement (RelyX Unicem), and conventional cement (zinc phosphate). The tensile force required for the removal of the LOCATOR abutments from their corresponding roots was recorded. Data were statistically analyzed with 2-way ANOVA and the Tukey multiple comparison test., Results: Both the cement type (P<.001) and the length of the LOCATOR abutment (P<.001) significantly affected the mean tensile forces. Dual-polymerized glass-reinforced resin cement (Parapost Paracore) presented significantly higher mean tensile forces for the LOCATOR abutment retention among all cements (P<.05)., Conclusions: Regardless of the length, LOCATOR abutments luted with Parapost Paracore resin cement presented higher mean resistance to tensile forces compared with those luted with the other cements. LOCATOR abutments of 6 mm in length were more resistant to tensile forces than those of 3 mm in length in combination with all cements., (Copyright © 2019 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Components have been introduced that allow the screw channel of an implant crown to be angled lingually and the screws to be tightened in a non-axial direction to the implant. Information is lacking as to how the removal torque value (RTV) and force to failure (FTF) of these components compare with those of conventional screws., Purpose: The purpose of this in vitro study was to evaluate and compare the RTV and FTF values of cyclically loaded implant-supported restorations. Specifically, values for conventional axially tightened gold screws were compared with those for non-axially tightened screws aligned at 3 different angulations., Material and Methods: A total of 28 external hexagon implants were embedded in acrylic resin and divided into 4 groups. Simulated restorations were fabricated on abutments capable of different screw channel angulations. Dynamic abutments (DA) were waxed at different angulations and then cast. Simulated restorations were placed on the implants and tightened: group 0GS: 0-degree angulation gold screw tightened to 35 Ncm (control group); group 0DAS, 0-degree angulation with dynamic abutment (DAS) screw; group 20DAS: 20-degree angulation with DA screw; group 28DAS: 28-degree angulation with DAS screw. In groups 0DAS, 20DAS, and 28DAS, the DAS screw was used and tightened to 25 Ncm. Screw removal torque values were recorded by using a digital torque gauge at baseline and, after reaching cyclic fatigue, by using a dual-axis mastication simulator for 1200000 cycles. The fracture strength (FS) of the implant restorations was tested under compression until failure by using a universal testing machine. Differences between baseline and removal torque (ΔRT) were calculated. Statistical analysis was performed by using 1-way ANOVA for ΔRT and FS separately (α=.05)., Results: ΔRT and FS values were not significantly different among the groups (P>.05). The screw fractured in 5 of 28 specimens (17.8%); the remaining specimens failed with fracture of the implant., Conclusions: The removal torque and FS values of the angulated abutment screw were comparable to those of the gold screw. Angulation of the abutment had no significant influence on the screw removal torque values., (Copyright © 2018 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: The decision to splint or to restore independently generally occurs during the planning stage, when the advantages and disadvantages of each clinical situation are considered based on the proposed treatment. However, clinical evidence to help clinicians make this decision is lacking., Purpose: The purpose of this systematic review and meta-analysis was to assess the marginal bone loss, implant survival rate, and prosthetic complications of splinted and nonsplinted implant restorations., Material and Methods: This study was designed according to the Cochrane criteria for elaborating a systematic review and meta-analysis and adopted the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. Also, this review was registered at the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42017080162). An electronic search in the PubMed/MEDLINE, Cochrane Library, and Scopus databases was conducted up to November 2017. A specific clinical question was structured according to the population, intervention, comparison, outcome (PICO) approach. The addressed focused question was "Should the restoration of adjacent implants be splinted or nonsplinted?" The meta-analysis was based on the Mantel-Haenszel and inverse variance methods to assess the marginal bone loss, implant survival, and prosthetic complications of splinted and nonsplinted implant restorations., Results: Nineteen studies were selected for qualitative and quantitative analyses. A total of 4215 implants were placed in 2185 patients (splinted, 2768; nonsplinted, 1447); the mean follow-up was 87.8 months (range=12-264 months). Quantitative analysis found no significant differences between splinted and nonsplinted restorations for marginal bone loss. The assessed studies reported that 75 implants failed (3.4%), of which 24 were splinted (99.1% of survival rate) and 51 were nonsplinted (96.5% of survival rate). Quantitative analysis of all studies showed statistically significant higher survival rates for splinted restorations than for nonsplinted restorations. Ceramic chipping, screw loosening, abutment screw breakage, and soft tissue inflammation were reported in the selected studies. The quantitative analysis found no statistically significant difference in the prosthetic complications of splinted and nonsplinted restorations., Conclusions: Within the limitations of this systematic review and meta-analysis, it was concluded that there was no difference in the marginal bone loss and prosthetic complications of splinted and nonsplinted implant restorations; this is especially true for restorations in the posterior region. However, splinted restorations were associated with decreased implant failure., (Copyright © 2018 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

The cause of some peri-implant problems may be primarily attributable to the design of the prosthesis. A screw-retained interim implant may be advisable for reversibility and to avoid peri-implant cement, although screw retention may be difficult for maxillary anterior implants with a labial angulation. In the treatment described, a interim screw-retained crown was attached to a dynamic abutment with a lingual screw access hole to obtain a correctly fitting restoration., (Copyright © 2018 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Retrievability of implant-supported restorations is important. Data are lacking for cemented zirconia crowns on zirconia abutments., Purpose: The purpose of this in vitro study was to investigate the influence of different cements and marginal discrepancy on the retrievability of implant-supported zirconia crowns. Furthermore, the influence of thermocycling on retrievability was evaluated., Material and Methods: Thirty tapered Camlog zirconia abutments (6-degree taper, 6×4.3 mm) were used. Thirty zirconia crowns with 3 different marginal cementation discrepancies (70, 130, 190 μm) were fabricated by using computer-aided design and computer-aided manufacturing (CAD-CAM) technology. Five cements for interim or semidefinitive cementation were used: eugenol-free zinc oxide (Freegenol) and acrylurethane (ImProv) and 3 different composite resin cements (X-Pand Implant, Dyna Implant, Telio CS Cem Implant). Specimens underwent either 3-day storage in sodium chloride or thermocycling (10 000 cycles). Crowns were removed by using a universal testing machine (UTM) and a clinical removal device. Data were analyzed using 1-way ANOVA and the Scheffé test (α=.05)., Results: Thermocycling decreased the retention force significantly (P<.001). Marginal discrepancy (70 to 190 μm) was not significantly influential on retrievability (P>.05). Therefore, groups were pooled according to the factor of marginal discrepancy. The mean retention force using the UTM after 3-day storage and thermocycling was as follows: Freegenol, 235 ±42 N (thermocycling, 29 ±9 N); Improv, 110 ±50 N (thermocycling, 35 ±38 N); Telio CS, 104 ±17 N (thermocycling, 6 ±10 N); Dyna implant, 61 ±17 N (thermocycling, 1 ±1 N); and X-Pand, 50 ±16 N (thermocycling, 2 ±2 N)., Conclusions: Retention forces of the tested cements were significantly different and decreased considerably after thermocycling. Marginal cementation discrepancy between 70 and 190 μm did not influence retrievability., (Copyright © 2018 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Recent research has shown that dynamic parameters correlate with insertion energy-that is, the total work needed to place an implant into its site-might convey more reliable information concerning immediate implant primary stability at insertion than the commonly used insertion torque (IT), the reverse torque (RT), or the implant stability quotient (ISQ). Yet knowledge on these dynamic parameters is still limited., Purpose: The purpose of this in vitro study was to evaluate whether an energy-related parameter, the torque-depth curve integral (I), could be a reliable measure of primary stability. This was done by assessing if (I) measurement was operator-independent, by investigating its correlation with other known primary stability parameters (IT, RT, or ISQ) by quantifying the (I) average error and correlating (I), IT, RT, and ISQ variations with bone density., Material and Methods: Five operators placed 200 implants in polyurethane foam blocks of different densities using a micromotor that calculated the (I) during implant placement. Primary implant stability was assessed by measuring the ISQ, IT, and RT. ANOVA tests were used to evaluate whether measurements were operator independent (P>.05 in all cases). A correlation analysis was performed between (I) and IT, ISQ, and RT. The (I) average error was calculated and compared with that of the other parameters by ANOVA. (I)-density, IT-density, ISQ-density, and RT-density plots were drawn, and their slopes were compared by ANCOVA., Results: The (I) measurements were operator independent and correlated with IT, ISQ, and RT. The average error of these parameters was not significantly different (P>.05 in all cases). The (I)-density, IT-density, ISQ-density, and RT-density curves were linear in the 0.16 to 0.49 g/cm³ range, with the (I)-density curves having a significantly greater slope than those regarding the other parameters (P≤.001 in all cases)., Conclusions: The torque-depth curve integral (I) provides a reliable assessment of primary stability and shows a greater sensitivity to density variations than other known primary stability parameters., (Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Zirconia prostheses show a high rate of retention loss, and more information is needed regarding the treatment of the intaglios of zirconia prostheses to improve the bond strength between zirconia and resin cement., Purpose: The purpose of this in vitro study was to evaluate the retention of titanium abutments and zirconia prostheses treated with silica-containing glass-ceramic liners. The effect of the abutment convergence angle on retention force was also examined., Material and Methods: Titanium abutments and zirconia copings (n=90) were fabricated with 3 different convergence angles (6, 12, and 24 degrees). Specimens were divided into 2 groups according to surface treatment: an airborne-particle-abraded control group and a group that was coated with a silica-containing glass-ceramic liner after airborne-particle abrasion (liner group). The thickness of the liner was measured, and the inner spacing of the zirconia coping was modified in the liner group. The coping was cemented, and the retention was evaluated with a tensile bond strength test by using a universal testing machine. Retention was analyzed by using a 2-way analysis of variance. Modes of failure were evaluated by examining the fracture surface. Elemental analysis of the interface was also performed., Results: The liner group showed a significantly higher retention force for the zirconia prosthesis (P<.05). Regardless of surface treatment, the retention force at a convergence angle of 6 degrees was higher than that at 24 degrees (P<.05). The control group showed mostly adhesive type failures, whereas the liner group exhibited mostly mixed type failures., Conclusions: Silica-containing glass-ceramic liner treatment increased the retention compared with airborne-particle abrasion treatment alone. Tensile bond strength increased with decreasing abutment convergence angle., (Copyright © 2018 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Two-piece abutments consisting of a prefabricated titanium luting base and a zirconia abutment are used widely in implant restorations. Straightforward and reliable procedures for bonding titanium and zirconia are necessary for ensuring low failure rates in such restorations., Purpose: The purpose of this in vitro study was to evaluate the tensile load of zirconia copings on prefabricated titanium abutments using 4 different self-adhesive resin cements., Material and Methods: A total of 128 industrially manufactured partially yttria-stabilized zirconia ceramic copings were bonded to titanium abutments with a luting space of about 60 μm or 100 μm. The bonding surfaces were airborne-particle abraded with 50 μm alumina and cleaned ultrasonically. The zirconia copings were bonded with Panavia SA Cement Automix (SA), RelyX Unicem 2 Automix (RU), MaxCem Elite (ME), or SmartCem 2 (SC). Specimens from each cement group were randomly assigned to be stored either in distilled water (37°C) for 3 days or subjected to 37 500 thermocycles over 150 days. After debonding in tension, failure modes (adhesive or cohesive) were analyzed, and basic fuchsin dye penetration tests were performed using optical microscopy and scanning electron microscopy. Three-way ANOVA and Tukey HSD tests were used for statistical analysis (α=.05)., Results: Three-way ANOVA results determined that the luting resin used and the luting space had a significant effect (P≤.002), while the storage time did not have an overall effect (P>.05). The interaction between the luting resin used and storage time was significant (P<.001). After storage for 3 days, the retentive force of SA (1002 N) was highest, followed by that for RU (614 N), ME (550 N), and SC (346 N) (P≤.05); the forces for RU and ME were not significantly different (P>.05). However, after thermocycling, RU had the highest retentive force (848 N), followed by SA (646 N), ME (475 N), and SC (364 N) (P≤.05). Retentive forces for ME and SC were not significantly different (P>.05). The failure modes of the zirconia abutment surfaces were predominantly adhesive, while those of the titanium surfaces were mainly cohesive. The SA specimens showed the lowest dye penetration, followed by the RU, ME, and SC specimens., Conclusions: The greatest mean retention was found with Panavia SA Cement Automix and RelyX Unicem 2 Automix with a luting space of 60 μm when bonding zirconia copings to titanium., (Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: A composite resin cement and matching self-etch adhesive was developed to simplify the dependable retention of lithium disilicate crowns. The efficacy of this new system is unknown., Purpose: The purpose of this in vitro study was to determine whether lithium disilicate crowns cemented with a new composite resin and adhesive system and 2 other popular systems provide clinically acceptable crown retention after long-term aging with monthly thermocycling., Material and Methods: Extracted human molars were prepared with a flat occlusal surface, 20-degree convergence, and 4 mm axial length. The axio-occlusal line angle was slightly rounded. The preparation surface area was determined by optical scanning and the analysis of the standard tessellation language (STL) files. The specimens were distributed into 3 cement groups (n=12) to obtain equal mean surface areas. Lithium disilicate crowns (IPS e.max Press) were fabricated for each preparation, etched with 9.5% hydrofluoric acid for 15 seconds, and cleaned. Cement systems were RelyX Ultimate with Scotch Bond Universal (3M Dental Products); Monobond S, Multilink Automix with Multilink Primer A and B (Ivoclar Vivadent AG); and NX3 Nexus with OptiBond XTR (Kerr Corp). Each adhesive provided self-etching of the dentin. Before cementation, the prepared specimens were stored in 35°C water. A force of 196 N was used to cement the crowns, and the specimens were polymerized in a 35°C oven at 100% humidity. After 24 hours of storage at 100% humidity, the cemented crowns were thermocycled (5°C to 55°C) for 5000 cycles each month for 6 months. The crowns were removed axially at 0.5 mm/min. The removal force was recorded and the dislodgement stress calculated using the preparation surface area. The type of cement failure was recorded, and the data were analyzed by 1-way ANOVA and the chi-square test (α=.05) after the equality of variances had been assessed with the Levene test., Results: The Levene test was nonsignificant (P=.936). The ANOVA revealed the mean removal stresses, and forces did not differ for RelyX Ultimate with Scotchbond Universal (3.9 MPa; 522 N) and Multilink Automix with Multilink Primer (3.7 MPa; 511 N); both differed significantly (P=.022) from the mean for NX3 Nexus with OptiBond XTR (2.9 MPa; 387 N). For all 3 cements, the modes of failure showed cement principally on the crown intaglio, and the chi-square analysis was nonsignificant (P=.601)., Conclusions: IPS e.max Press (lithium disilicate) crowns were well retained (2.9-3.9 MPa; 387-522 N) by the 3 cement-adhesive combinations after 6 months of aging with monthly thermocycling. These results can serve as a basis for cement selection for this type of crown because the values significantly exceeded those for zinc phosphate. Cements using their matched dentin bonding agent as the ceramic primer were as successful as cements with a separate silane coupling agent., (Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: The best procedure for cementing a restoration to zirconia implants has not yet been established., Purpose: The purpose of this in vitro study was to measure the retention of polymer-infiltrated ceramic crowns to zirconia 1-piece implants using a wide range of cements. The effect of ceramic primer treatment on the retention force was also recorded. The retention results were correlated with the shear bond strength of the cement to zirconia and the indirect tensile strength of the cements to better understand the retention mechanism., Material and Methods: The retention test was performed using 100 polymer-infiltrated ceramic crowns (Vita Enamic) and zirconia implants (ceramic.implant CI) The crowns were cemented with either interim cement (Harvard Implant semipermanent, Temp Bond), glass-ionomer cement (Ketac Cem), self-adhesive cement (Perma Cem 2.0, RelyX Unicem Automix 2, Panavia SA), or adhesive cement (Multilink Implant, Multilink Automix, Vita Adiva F-Cem, RelyX Ultimate, Panavia F 2.0, Panavia V5 or Panavia 21) (n=5). Additionally ceramic primer was applied on the intaglio crown surface and implant abutment before cementation for all adhesive cements (Multilink Implant, Multilink Automix: Monobond plus; RelyX Ultimate Scotchbond Universal; Vita Adiva F-Cem: Vita Adiva Zr-Prime; Panavia F2.0, Panavia V5: Clearfil Ceramic Primer) and 1 self-adhesive cement containing 10-methacryloyloxydecyl dihydrogen phosphate (MDP) (Panavia SA: Clearfil Ceramic Primer). Crown debond fracture patterns were recorded. Shear bond strength was determined for the respective cement groups to polished zirconia (n=6). The diametral tensile strength of the cements was measured (n=10). Statistical analysis was performed using 1-way or 2-way analysis of variance followed by the Fisher LSD test (α=.05) within each test parameter., Results: Adhesive and self-adhesive resin cements had shear bond strength values of 0.0 to 5.3 MPa and revealed similar retention forces. Cements containing MDP demonstrated shear bond strength values above 5.3 MPa and displayed increased retention. The highest retention values were recorded for Panavia F 2.0 (318 ±28 N) and Panavia 21 (605 ±82 N). All other adhesive and self-adhesive resin cements attained retention values between 222 ±16 N (Multilink Automix) and 270 ±26 N (Panavia SA), which were significantly higher (P<.05) than glass-ionomer (Ketac Cem: 196 ±34 N) or interim cement (Harvard Implant semipermanent: 43 ±6 N, Temp Bond: 127 ±13 N). Application of manufacturer-specific ceramic primer increased crown retention significantly only for Panavia SA., Conclusions: Products containing MDP provided a high chemical bond to zirconia. Self-adhesive and adhesive resin cements with low chemical bonding capabilities to zirconia provided retention force values within a small range (220 to 290 N)., (Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Dental research is rich with articles that investigated the influence of host-site variables, some implant-related variables (implant length, diameter, taper, design, location, and surface topography), different loading protocols or surgical procedures, and measurement methodology on dental implant stability. However, the number of implants and its effect on implant stability remain unclear., Purpose: The purpose of this randomized clinical trial was to investigate the influence of implant number on implant stability by comparing 2 versus 4 implants in mandibular implant overdentures., Material and Methods: The trial included 20 participants with edentulous mandibular ridges. Participants were randomly assigned to 2 equal groups, a 4-implant (experimental) group consisting of 4 implants installed in lateral-canine and premolar regions; and a 2-implant (control) group, consisting of 2 implants in lateral-canine regions. Implant stability was measured using resonance frequency analysis at implant placement and then at 1, 3, 6, 9, and 12 months. The Student t test was used to compare the implant stability quotient (ISQ) values of the anterior implants in the 4-implant and 2-implant groups. One-way ANOVA followed by the post hoc Bonferroni test was used to compare ISQ values among the different follow-up periods within each group (α=.05)., Results: Mean ISQ values for anterior implants in the 4-implant group were slightly higher than those recorded for the 2-implant group at all follow-up periods. However, these differences were not statistically significant (P>.05). Within-group comparison revealed an initial decrease in implant stability for all implants. This decrease was statistically significant for the 2-implant group (P<.001) and for posterior implants in the 4-implant group (P<.001). This was then followed by a gradual increase in ISQ values for all implants in both groups., Conclusions: Increasing the number of implants from 2 to 4 in mandibular implant overdentures did not have a significant influence on implant stability., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: New production methods have been developed for metal-ceramic restorations. Different production methods may show different surface roughness and fit, which may affect retention and long-term success., Purpose: The purpose of this in vitro study was to examine 3 different production methods with regard to surface roughness, marginal and internal fit, and retention of cobalt-chromium alloy single-crown copings., Material and Methods: A master abutment of a premolar mandibular tooth preparation with 4-mm height and a 0.6-mm deep 120-degree chamfer finish line with a 12-degree angle of convergence was replicated in die stone and scanned. Thirty-six cobalt-chromium alloy copings were produced using 3 different production techniques. Twelve copings were produced by laser-sintering, 12 by milling, and 12 by milled wax/lost wax. The surface microstructure of 2 copings in each group was analyzed using interferometry. The remaining 10 copings in each group were used to evaluate marginal and internal fit by using an impression material replica method, and retention was evaluated by using a uniaxial tensile force pull-off test. The copings from each test group were cemented with zinc phosphate cement onto resin abutments. Statistical analyses of differences in marginal and internal fit were performed using 1-way ANOVA and the Mann-Whitney U test. Differences in surface topography were analyzed with the Kruskal-Wallis and Mann-Whitney U tests for nonparametric data. Differences in retentive values were analyzed using the Mann-Whitney U test for nonparametric data (all α=.05)., Results: Differences in surface microstructure were seen. The laser-sintered copings showed increased surface roughness compared with milled and milled wax/lost wax copings. Differences in marginal and internal fit were noted. Laser-sintered showed significantly smaller spaces between coping and abutment than milled wax/lost wax copings (P=.003). At the margins, laser-sintered copings showed significantly smaller spaces than either the milled wax/lost wax group (P=.002) or the milled group (P=.002). At the chamfer, laser-sintered copings showed significantly smaller spaces than milled wax/lost wax copings (P=.005). At the center of the axial walls, laser-sintered copings showed significantly smaller spaces than those in the milled wax/lost wax (P=.004) and milled copings (P=.005). No significant differences were noted between milled and milled wax/lost wax copings (P>.05). No significant differences were detected regarding retentive forces in the pull-off tests (P>.05)., Conclusions: Laser-sintered Co-Cr crown copings showed increased surface roughness and better internal and marginal fit than copings produced by milling or milled wax/lost wax technique. However, the crown pull-off tests did not reveal any significant differences., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Parallel labiolingual walls and the preservation of the cingulum in anterior tooth preparations have been advocated. However, their contribution to retention and resistance form has not been evaluated., Purpose: The purpose of this in vitro study was to evaluate the retention and resistance failure loads of 2 preparation designs for maxillary anterior teeth., Material and Methods: Forty metal restorations were fabricated and paired with 40 cobalt-chromium prepared tooth analogs. Twenty of the specimens had parallel buccolingual walls at the cervical part (group PBLW; the control group), whereas the remaining 20 had converging buccolingual walls (group CBLW; the experimental group). The restorations were cemented to the tooth analogs with a resin-modified glass ionomer luting agent. Ten specimens from each group were subjected to tensile loading with a universal testing machine; the rest were subjected to compression loading until failure. Descriptive statistics and the independent t test (α=.05) were used to determine the effect of failure loads in the tested groups., Results: The independent t test revealed statistically significant differences between the tested groups in tensile loading (P<.001) and in compressive loading (P<.001). The PBLW group presented a higher tensile failure load than the CBLW. On the contrary, the PBLW group presented a smaller compression failure load than the CBLW., Conclusions: Parallelism of the buccolingual axial walls in anterior maxillary teeth increased the retention form but decreased the resistance form., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: The optimal retention of implant-supported ceramic crowns on zirconia abutments is a goal of prosthodontic treatment., Purpose: The purpose of this in vitro study was to evaluate the retentive strength of implant-supported IPS e.max CAD-CAM (e.max) crowns bonded to custom zirconia implant abutments with different cements., Material and Methods: An optical scan of a zirconia custom abutment and a complete-coverage modified crown was designed using an intraoral E4D scanner. One hundred twenty lithium disilicate crowns (IPS e.max CAD) were cemented to 120 zirconia abutment replicas with 1 of 6 cements: Panavia 21 (P21), Multilink Hybrid Abutment (MHA), RelyX Unicem 2 (RXU), RelyX Luting Plus (RLP), Ketac Cem (KC), and Premier Implant (PI). The specimens were stored at 37°C in 100% humidity for 24 hours. Half of the specimens were thermocycled for 500 cycles. The retentive force was measured using a pull-out test with a universal testing machine. Mean retentive strengths (MRS) were calculated using 2-way ANOVA and the Tukey-Kramer test (α=.05)., Results: The MRS (MPa) after 24-hour storage were P21 (3.1), MHA (2.5), RXU (2.5), RLP (1.3), KC (0.9), and PI (0.5). The MRS after thermocycling were MHA (2.5), P21 (2.2), RLP (1.8), KC (1.4), RXU (1.1), and PI (0.3). P21 had the highest MRS after 24-hour storage (P<.001), but after thermocycling MHA had the highest MRS (P<.001). RXU showed a significant decrease in MRS after thermocycling (P<.05). Cement residue was mostly retained on the zirconia abutments for P21, while for the other cements' residue was retained on the lithium disilicate crowns., Conclusions: The cements tested presented a range of retentive strengths, providing the clinician with a choice of more or less retentive cements. MHA was the most retentive cement after thermocycling. Thermocycling significantly affected the retentive strengths of the P21 and RXU cements., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Presently, no studies have evaluated clinical outcomes or patient-centered outcomes for complete dentures fabricated with computer-aided design and computer aided manufacturing (CAD/CAM) technology., Purpose: The purpose of this prospective cohort pilot study was to evaluate the clinical and patient-centered outcomes for CAD/CAM monolithic dentures fabricated in 2 visits., Material and Methods: Twenty participants with an existing set of maxillary complete dentures opposing either mandibular complete dentures or implant-retained overdentures that required replacement were recruited in this study. A 2-visit duplicate denture protocol was used to fabricate 40 arches of monolithic dentures with CAD/CAM technology. A 100-mm visual analog scale (VAS) instrument was then used to record 12 outcomes at baseline and at 1-year follow-up. Predetermined values were assigned to grade the VAS rating of each outcome as favorable (70.1-100) and unfavorable (≤70). Favorable ratings were sub-divided as excellent (90.1-100), good (80.1-90), and fair (70.1-80). The clinical outcomes were evaluated independently by 2 experienced prosthodontists at baseline and at 1-year follow-up. Patients evaluated the corresponding patient-centered outcomes during the same time intervals. Additional descriptive variables were also recorded. Each clinical and patient-centered outcome was summarized by medians and ranges. Differences in all ratings recorded at baseline and at 1 year were tested by 1-sided sign test (α=.05)., Results: Of 20 participants, 3 were lost to follow-up, and 3 were unsatisfied with the digital dentures and withdrew from the study. These 3 participants were considered treatment failures. Of the 14 remaining participants, 9 had implant-retained mandibular overdentures, and 5 had conventional mandibular complete dentures. For clinical outcomes, the 12 studied outcomes were favorably evaluated by the 2 prosthodontist judges at the 1-year follow-up. Evaluations showed minimal differences between baseline and 1 year. An average of 5 emails (0-11) per patient were sent to the laboratory technicians to communicate the improvisation the CAD design of the dentures. An average of 3.3 denture adjustments were needed after insertion (0-10) during the 1-year period. For patient-centered outcomes, median ratings of all 14 participants indicated each of the 12 studied outcomes was favorable at the 1-year recall. Statistically significant improvements in patient ratings from baseline to 1 year were observed for the absence of denture sore spots and treatment time to make the dentures (P<.05). Minor complications related to loss of retention, excessive wear of teeth and the need for additional visits were observed in 5 participants. No other adverse clinical outcomes related to the CAD/CAM dentures were noted in the 14 evaluated participants, and all dentures were intact and in good condition at the 1-year follow-up., Conclusions: Clinical and patient-centered outcomes for CAD/CAM monolithic dentures fabricated using a 2-visit protocol were evaluated favorably at a 1-year follow-up. However, the proportion of excellent and good ratings for overall satisfaction and assessment was higher for patients than clinicians. A considerable amount of the clinician's time and effort was devoted to aiding in the digital process for the fabrication of CAD/CAM dentures., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: No consensus has been reached on which retention system, cement- or screw-retained, is best to avoid bone loss around the implant of a fixed implant-supported restoration., Purpose: The purpose of this systematic review and meta-analysis was to compare cement- and screw-retained retention systems in fixed implant-supported restorations in terms of marginal bone loss, implant survival, and prosthetic complications., Material and Methods: A comprehensive search of studies published from January 1995 to March 2015 and listed in the PubMed/MEDLINE, Embase, Scopus and the Cochrane Library databases was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The meta-analysis was based on the Mantel-Haenszel and inverse variance methods. Marginal bone loss was the continuous outcome measure evaluated by mean difference (MD), and implant survival and prosthetic complications were the dichotomous outcome measures evaluated by risk ratio (RR), both with corresponding 95% confidence intervals (CI)., Results: The 20 studies selected for review evaluated 2139 participants, whose mean age was 47.14 years and who had received 8989 dental implants. The mean follow-up was 65.4 months (range: 12-180 months). Results of the MD for marginal bone loss showed statistically significant differences in favor of the cement-retained prosthesis (P =.04; MD: -0.19; CI: -0.37 to -0.01). The implant survival rate was higher for the cement-retained prosthesis (P =.01; RR: 0.49; CI: 0.28 to 0.85), and the prosthetic complication rate was higher for the screw-retained prosthesis (P =.04; RR: 0.52; CI: 0.28 to 0.98). Additional analysis of the mean plaque index did not show differences between retention systems (P=.58; MD: 0.13; CI: -0.32 to 0.57)., Conclusions: The current meta-analysis indicated that cement-retained, fixed implant-supported restorations showed less marginal bone loss than screw-retained, fixed implant-supported restorations during the follow-up period, which ranged from 12 to 180 months. However, the small difference between the mean values may not show clinical significance. The rates of prosthetic complication and implant survival also compared favorably with cement-retained prostheses., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

The purpose of this technique was to eliminate excess cement from the implant restoration by using a 2-step cementation process. A custom acrylic resin abutment, a duplicate of the titanium abutment, is fabricated before the restoration is cemented. At cementation, cement is placed inside the restoration, which is placed onto the acrylic resin abutment outside the mouth. The majority of the excess cement from inside the restoration is expressed onto the acrylic resin abutment. The restoration is then placed on the titanium abutment inside the mouth. The result is a minimum amount of excess cement expressed intraorally. This technique minimizes the adverse biological consequences of leaving excess cement beneath implant-supported restorations., (Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Limited information is available regarding the accuracy of mechanical torque-limiting devices (MTLDs) after their clinical use., Purpose: The purpose of this study was to determine the accuracy of 2 types of MTLDs (friction-style and spring-style) after clinical use., Material and Methods: Twenty-seven MTLDs in clinical service at The Ohio State University College of Dentistry were collected. Thirteen were friction-style and 14 were spring-style. A total of 6 different dental implant companies were represented (Astra Tech, Zimmer Dental, Biomet 3i, Straumann, Nobel Biocare, and Thommen Medical). All MTLDs had been in use for at least 6 months without being recalibrated, and all were tested to determine their accuracy in delivering target torque values. Statistical analysis used nonparametric tests to determine the accuracy of the MTLDs in delivering target torque values, and Bonferroni post hoc tests were used to assess pairwise comparisons., Results: After clinical service, spring-style MTLDs were significantly more accurate than friction-style MTLDs (P<.05)., Conclusions: Within the limitations of this study, it was concluded that after clinical service, spring-style MTLDs were more accurate than friction-style MTLDs. All MTLDs delivered torque values within 10% of the target torque value., (Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Currently, appropriate access to the abutment screw within cement-retained implant restorations is determined using labor-intensive techniques. The introduction of computer-aided design/computer-aided manufacture technology has facilitated a digitized fabrication process to yield a template that can enhance the accuracy of drilling a screw channel. This article describes the method used to create these guide templates by using advanced dental design programs and machining., (Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

The existing techniques for drilling a screw access hole in cement-retained restorations are limited by inaccurate drill guidance and ineffective cooling of the drilling area. An approach for fabricating a guide template to provide screw retrievability using computer-aided design and computer-aided manufacturing (CAD/CAM) is described. A handpiece sleeve was made by 3-dimensional printing and incorporating it into a vacuum-formed template. The handpiece sleeve not only guides the head of the handpiece accurately but also enables the cooling water to reach the area of drilling directly., (Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

This clinical report describes the treatment of a patient with anatomic and biomechanical problems that made retrievability of an implant-supported prosthesis a design priority. During treatment, the patient was found to be intolerant of local anesthesia, prompting an alternative retrievable design from the screw-retained interim restoration. A channel retention technique for fixed implant superstructures is presented., (Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Unlike conventional loading protocols, the immediate loading of single implants has not been fully investigated., Purpose: The purpose of this study was to assess the prosthetic and esthetic periimplant mucosal outcomes of immediately restored dental implants during a 1-year follow-up., Material and Methods: Twenty participants meeting the established inclusion criteria received double-threaded, tapered body dental implants (SuperLine; Dentium). Implants were placed and stabilized at a minimum of 35 Ncm of torque and restored immediately after the surgery with interim restorations. These were replaced with definitive restorations 6 months after implant placement. Clinical measurements at each visit included resonance frequency analysis, the evaluation of the participants' oral health (gingival and plaque indices), and the esthetic outcome of the interim or definitive restoration., Results: Implants placed in this clinical study had a 100% success rate. The oral health and esthetic outcomes were favorable for all participants., Conclusions: Double-threaded, tapered body dental implants that were placed and immediately restored with fixed interim prostheses and with definitive prostheses after 6 months remained stable and functional after 1 year., (Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Bond stability between zirconia crowns and luting cement and between cement and dentin is a main concern; however, only limited evidence is available as to its longevity., Purpose: The purpose of this in vitro study was to measure the retentive strengths of 7 self-adhesive cements (RelyX Unicem Aplicap, RelyX Unicem Clicker, RelyX Unicem 2 Automix, iCEM, Maxcem Elite, Bifix SE, SpeedCem), 2 adhesive cements with self-etch primers (Panavia 21, SEcure), 1 glass ionomer cement (Ketac Cem), 1 resin-modified glass ionomer cement (Meron Plus), and 1 zinc phosphate cement for luting zirconia crowns (LAVA) to extracted teeth after thermocycling with or without 1 year of water storage., Material and Methods: Two-hundred-forty extracted human molars (2 treatments; n=10 per cement) were prepared in a standardized manner. All cements were used according to the manufacturers' recommendations. The intaglios of the crowns were treated with airborne-particle abrasion. After thermocycling (×5000, 5°C/55°C) with or without 1 year of water storage, the cemented ceramic crowns were removed by using a Zwick universal testing device. Statistical analyses were done with the Wilcoxon rank sum and the 2-independent-samples Kolmogorov-Smirnov test., Results: Median retentive strengths [MPa] for specimens thermocycled only/thermocycled with 1 year of water storage were as follows: Panavia 21: 1.7/2.5, SEcure: 3.0/3.0, RelyX Unicem Aplicap: 3.1/3.4, RelyX Unicem Clicker: 4.1/4.2, RelyX Unicem 2 Automix: 3.8/3.1, iCEM: 2.3/2.7, Maxcem Elite: 3.0/3.2, Bifix SE: 1.7/1.7, SpeedCem: 1.3/1.6, Meron Plus: 3.1/2.7, Ketac Cem: 1.4/1.4, and zinc phosphate cement: 1.1/1.6. Statistically significant differences were found only among specimens thermocycled only or thermocycled with 1-year water storage (P<.001)., Conclusions: Significant differences in retentive strengths were observed among cements after thermocycling only or thermocycling with 1 year of water storage, but not for the effect of the additional 1 year of water storage., (Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: The geometries of tooth preparations are important features that aid in the retention and resistance of cemented complete crowns. The clinically relevant values and the methods used to measure these are not clear., Purpose: The purpose of this systematic review was to retrieve, organize, and critically appraise studies measuring clinical tooth preparation parameters, specifically the methodology used to measure the preparation geometry., Material and Methods: A database search was performed in Scopus, PubMed, and ScienceDirect with an additional hand search on December 5, 2013. The articles were screened for inclusion and exclusion criteria and information regarding the total occlusal convergence (TOC) angle, margin design, and associated measuring methods were extracted. The values and associated measuring methods were tabulated., Results: A total of 1006 publications were initially retrieved. After removing duplicates and filtering by using exclusion and inclusion criteria, 983 articles were excluded. Twenty-three articles reported clinical tooth preparation values. Twenty articles reported the TOC, 4 articles reported margin designs, 4 articles reported margin angles, and 3 articles reported the abutment height of preparations. A variety of methods were used to measure these parameters., Conclusions: TOC values seem to be the most important preparation parameter. Recommended TOC values have increased over the past 4 decades from an unachievable 2- to 5-degree taper to a more realistic 10 to 22 degrees. Recommended values are more likely to be achieved under experimental conditions if crown preparations are performed outside of the mouth. We recommend that a standardized measurement method based on the cross sections of crown preparations and standardized reporting be developed for future studies analyzing preparation geometry., (Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: The mechanical properties of polyetheretherketone (PEEK) make it an ideal material for fixed dental prostheses; however, insufficient information is available about the cementation of these restorations., Purpose: The purpose of this study was to evaluate the retention strength of differently pretreated and conditioned PEEK crowns luted to dental abutments., Material and Methods: Human teeth were prepared in a standardized manner, and PEEK crowns were milled (N=160, n=10 per group) and conditioned as follows: airborne-particle abrasion, sulfuric etching, piranha etching, and no conditioning. These groups were divided into adhesive systems: visio.link, Signum PEEK Bond, Ambarino P60, and no adhesive and luted to dentin abutments. After water storage (60 days) and thermocycling (5000 cycles, 5°C/55°C), the retention strength of the crowns was determined with a pull-off test, and failure types were classified. The data were analyzed with the Kruskal-Wallis, 1-way ANOVA, and χ(2) test (α=.05)., Results: Crowns that were unconditioned and piranha etched and/or adhesively untreated or pretreated with Ambarino P60 had the lowest retention strength. The highest values were found for the airborne-particle abrasion and sulfuric etched groups and/or crowns adhesively pretreated with Signum PEEK Bond and visio.link. Composite resin cement that remained on dentin was observed more frequently for unconditioned groups in combination with Ambarino P60 and no adhesive pretreatment. Mixed failure types were found more frequently in the airborne-particle abrasion group in combination with visio.link, Signum PEEK Bond, and no adhesive pretreatment, in the sulfuric acid etched group combined with Ambarino P60 and no adhesive pretreatment, and after the piranha acid pretreatment in combination with visio.link or Signum PEEK Bond., Conclusions: The adhesion of the tested PEEK crowns to dentin was satisfactory after treatment with airborne-particle abrasion or etching with sulfuric acid and/or when additional adhesive systems such as visio.link or Signum PEEK Bond were used., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Recently a new therapeutic concept of patient-specific implant dentistry has been advanced based on computer-aided design/computer-aided manufacturing technology. However, a comprehensive study of the design and 3-dimensional (3D) printing of the customized implants, their mechanical properties, and their biomechanical behavior is lacking., Purpose: The purpose of this study was to evaluate the mechanical and biomechanical performance of a novel custom-made dental implant fabricated by the selective laser melting technique with simulation and in vitro experimental studies., Material and Methods: Two types of customized implants were designed by using reverse engineering: a root-analog implant and a root-analog threaded implant. The titanium implants were printed layer by layer with the selective laser melting technique. The relative density, surface roughness, tensile properties, bend strength, and dimensional accuracy of the specimens were evaluated. Nonlinear and linear finite element analysis and experimental studies were used to investigate the stress distribution, micromotion, and primary stability of the implants., Results: Selective laser melting 3D printing technology was able to reproduce the customized implant designs and produce high density and strength and adequate dimensional accuracy. Better stress distribution and lower maximum micromotions were observed for the root-analog threaded implant model than for the root-analog implant model. In the experimental tests, the implant stability quotient and pull-out strength of the 2 types of implants indicated that better primary stability can be obtained with a root-analog threaded implant design., Conclusions: Selective laser melting proved to be an efficient means of printing fully dense customized implants with high strength and sufficient dimensional accuracy. Adding the threaded characteristic to the customized root-analog threaded implant design maintained the approximate geometry of the natural root and exhibited better stress distribution and primary stability., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: The mechanical stability of the implant-abutment connection is of fundamental importance for successful implant-supported restorations. Therefore, understanding removal torque values is essential., Purpose: The purpose of this study was to evaluate the reverse torque values of indexed and nonindexed abutments of the Morse Taper system., Material and Methods: Twelve Morse taper implants with their respective abutments were divided into 2 groups (n=6): group NI, nonindexed abutments; and group IN, indexed abutments. Each abutment received a sequence of 2 consecutive torques for insertion (15 Ncm) at an interval of 10 minutes, and 1 reverse torque, all measured with a digital torque wrench. The Student t test with a 5% significance level was used to evaluate the data., Results: Statistical analysis showed no significant difference in reverse torque values between nonindexed and indexed abutments (P=.57). When comparing insertion torque and reverse torque values between the groups, group NI presented a mean torque loosening percentage of 8% (P=.013), whereas group IN presented a loosening of 15.33% (P<.001)., Conclusion: The use of indexed abutments for the Morse taper system presented similar biomechanical stability when compared with nonindexed abutments, both with a significant reduction in reverse torque values., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Ceramic single crowns fabricated from newer materials, especially zirconia, have shown relatively high survival rates. However, early reversible complications may increase the risk of an irreversible failure later., Purpose: The purpose of the study was to evaluate the early complications and short-term failures of zirconia single crowns and partial fixed dental prostheses (FDPs) made by predoctoral dental students., Material and Methods: Data were collected from the patient records. Altogether, 264 zirconia single crowns and 120 FDPs (342 abutments and 190 pontics) were fabricated for 173 patients between 2007 and 2010. Early complications were recorded during the prosthetic treatment phase, and short-term failures were recorded during the first year in use., Results: The most frequent early complications were localized gingival irritation (1.9% of single crowns and 2.5% of FDP) and postoperative tooth sensitivity (0.4% of single crowns and 3.3% of FDPs). Pulp exposure during preparation was recorded in 3 abutment teeth of the FDPs. The most frequent short-term failure was chipping of the veneering porcelain (0.8% for single crowns, 0.8% for FDPs). One crown lost cementation because of poor retention (0.4%), and 2 FDPs failed because of framework fractures (1.7%)., Conclusions: The most frequent early complications were localized gingival irritation and postoperative tooth sensitivity, and the most frequent short-term failure was chipping of the veneering porcelain., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Although 1-piece implants are associated with positive clinical outcomes, including improved implant stability, overall survival rate, and marginal bone levels, a few studies have suggested that 1-piece implants have low success rates., Purpose: This prospective multicenter study evaluated the efficacy of 1-piece implants placed in immediate function in private clinic-based and hospital-based settings with a focus on marginal bone level changes and esthetic outcomes over a 3-year follow-up period., Material and Methods: A total of 93 one-piece implants (29 maxillary, 64 mandibular) were placed in 63 participants (25 men and 38 women) at 1 university hospital and 3 private clinics. The implants were restored with interim crowns immediately after placement. Clinical and radiographic evaluations of marginal bone level, implant stability, periimplant mucosa, and plaque and papilla indices were performed at the time of implantation and after 6, 12, 24, and 36 months., Results: The 3-year cumulative implant survival rate was 100%. After implant placement, mean bone levels changed from -0.16 ±1.41 mm at 24 months to 0.40 ±1.46 mm at 36 months. Clinical parameters, including implant stability, periimplant mucosa, and plaque index, remained stable from 3 to 36 months during follow-up. The papilla index score increased over time., Conclusions: Within the limitations of this prospective study, marginal bone level was maintained, soft tissue integration was achieved, and a cumulative survival rate of 100% was obtained for 1-piece implants. The present findings indicate that 1-piece implants are an effective treatment option for immediate function situations., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: A validated universal method requiring no human input is needed to capture and evaluate preparation geometries in a manner that can be used to see the correlation of different parameters., Purpose: The purpose of this study was to present a method of capturing and evaluating crown preparation geometry., Material and Methods: One manually machined acrylic resin block and 9 randomly selected preparations for ceramic complete crowns prepared by general dentists were selected and prepared. The specimens were scanned (3D scanner; Nobel Biocare), and buccolingual and mesiodistal cross section images were collected. The images were imported into digitizing software (Engauge Digitizer 4.1) to convert the outlines into x and y coordinates. Six points were chosen by using a set of algorithms, and the resulting parameters were calculated., Results: The acrylic resin block was milled with a 12 degree total occlusal convergence (TOC) instrument producing a 12.83 degree TOC. For the other specimens, average TOC values ranged from 18 degrees to 52 degrees. The mean average margin width was 0.70 mm, and the mean average base dimension was 6.23 mm. The surface area/volume ratio, resistance length, and limiting taper were also calculated., Conclusions: The method described provides a basis for accurately evaluating preparation geometry without human input., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

An immediate surgical obturator is necessary for maxillectomy procedures to minimize functional disabilities in speech, swallowing, and egress of food and liquid into the surgical defect. Sometimes the extent of the tumor may be such that it may even require the removal of the maxillary sinus along with resection of the orbital floor. The resected orbital floor can be surgically reconstructed with autogenous soft and/or hard tissues or with alloplastic materials. This clinical report highlights one such situation where the surgical resection of the maxilla and the orbital floor were rehabilitated with an immediate surgical obturator extending to the orbital floor to support the visual apparatus., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: The effect of managing the screw access channels of zirconia implant abutments in the esthetic zone has not been extensively evaluated., Purpose: The purpose of this study was to determine the effect of an insert placed within the screw access channel of an anterior zirconia implant abutment on the amount of cement retained within the restoration-abutment system and on the dislodging force., Material and Methods: Thirty-six paired zirconia abutments and restorations were fabricated by computer-aided design and computer-aided manufacturing and were divided into 3 groups: open abutment, with the screw access channel unfilled; closed abutment, with the screw access channel sealed; and insert abutment, with a thin, tubular metal insert projection continuous with the screw head and placed into the abutment screw access channel. The restorations were cemented to the abutments with preweighed eugenol-free zinc oxide cement (TempBond NE). Excess cement was removed, and the weight of the cement that remained in the restoration-abutment system was measured. Vertical tensile dislodging forces were recorded at a crosshead speed of 5 mm/min after incubation in a 37°C water bath for 24 hours. The specimens were examined for the cement flow pattern into the screw access channel after dislodgement. Data were analyzed with ANOVA, followed by multiple comparisons by using the Tukey honestly significant difference test (α = .05)., Results: The mean (standard deviation) of retentive force values ranged from 108.1 ± 29.9 N to 148.3 ± 21.0 N. The retentive force values differed significantly between the insert abutment and both the open abutment (P < .05) and closed abutment groups (P < .01). Distinct patterns of cement failure were noted. The weight of the cement that remained in the system differed significantly, with both open abutment and insert abutment being greater than closed abutment (P < .05)., Conclusion: Modifying the internal configuration of the screw access channel of an esthetic zirconia implant abutment with a metal insert significantly affected both the cement retained within the abutment itself and the retention capabilities of the zirconia restoration cemented with TempBond NE cement., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: The retention of cement-retained implant-supported restorations can be affected by the height of the abutments., Purpose: The purpose of this study was to evaluate the effects of the surface treatment on the retention of implant-supported zirconia restorations over short abutments., Material and Methods: Eighty solid abutments reduced to 3 mm in height and their corresponding fixture replicas were embedded vertically in autopolymerizing acrylic resin blocks. Eighty zirconia copings (Cercon) with an occlusal loop were fabricated and divided into 2 groups (n=40). One group was airborne-particle abraded with 110 μm aluminium oxide and the other group was treated with silica coating (Rocatec System). Each group was then divided into 4 subgroups (n=10). The subgroups received either no treatment (control) or were treated with silane (Clearfil Porcelain Bond Activator+SE Primer), acid etching followed by silane, or ceramic primer (Clearfil). All copings were luted with a self-adhesive luting agent (Clearfil SA). After 1 week of conditioning in artificial saliva and thermal cycling (5000 cycles, 5°C-55°C), the removal force of the copings were tested with a universal testing machine at a 5 mm/min crosshead speed. The dislodgment force and failure mode were recorded. Two-way ANOVA and the Tukey honestly significant difference and the Fisher exact tests were used for data analysis (α=.05)., Results: The highest retentive values were obtained for airborne-particle abrasion--ceramic primer (228.84 N) and silica coating--ceramic primer (230.37 N), which were not significantly different from silica coating alone (216.26 N; P=.95) or a combination of airborne-particle abrasion followed by silanation (211.67 N; P=.87). The failure mode was primarily adhesive and cement principally remained on the copings., Conclusions: Within the limitations of this study, ceramic primer that contains adhesive phosphate monomer significantly improved the retention of zirconia ceramic restorations. Silicoating as a mechanical treatment provided greater retention for zirconia copings than airborne-particle abrasion when a resin-luting agent was used., (Copyright © 2014 The Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Information about the influence of zirconia crown surface treatment and cement type on the retention of zirconia crowns is limited. It is unclear whether zirconia crowns require surface treatment to enhance their retention., Purpose: The purpose of this in vitro study was to evaluate the effect of surface treatment on the retention of zirconia crowns cemented with 3 different adhesive resin cements after artificial aging., Material and Methods: Ninety extracted human molars were prepared for ceramic crowns (approximately 20-degree taper, approximately 4-mm axial length) and were divided into 3 groups (n=30). Computer-aided design and computer-aided manufacturing zirconia copings were fabricated. Three surface treatments were applied to the intaglio surface of the copings. The control group received no treatment, the second group was airborne-particle abraded with 50 μm Al2O3, and the third group was treated with 30 μm silica-modified Al2O3, The copings were luted with a self-etch (RelyX Unicem 2), a total-etch (Duo-Link), or a self-etch primer (Panavia F 2.0) adhesive cement. They were stored for 24 hours at 37°C before being artificially aged with 5000 (5°C-55°C) thermal cycles and 100,000 cycles of 70 N dynamic loading. Retention was measured on a universal testing machine under tension, with a crosshead speed of 0.5 mm/min. Statistical analysis was performed with 1-way and 2-way ANOVA., Results: Mean retention values ranged from 0.72 to 3.7 MPa. Surface treatment increased crown retention, but the difference was not statistically significant (P>.05), except for the Duo-Link cement group (P<.05). Analysis of the adhesives revealed that the Duo-Link cement resulted in significantly lower crown retention (P<.05) than the other 2 cements., Conclusion: For zirconia crowns, retention seems to be dependent on cement type rather than surface treatment., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: In response to the Commission of Dental Accreditation (CODA) mandate of a competency in the "replacement of teeth including fixed, removable and implant" prostheses, a predoctoral implant curriculum was implemented at New York University College of Dentistry. The assessment of the success or failure of a program should include an assessment of patient satisfaction with the treatment received in the predoctoral clinics., Purpose: The purpose of this study was to measure patient satisfaction with the mandibular 2-implant-retained overdenture therapy received in the predoctoral program at New York University College of Dentistry., Material and Methods: A telephone survey of patients who received an implant-retained overdenture in the predoctoral clinics at New York University, College of Dentistry (n=101) was conducted. Two of the authors contacted patients for participation in the survey and, using a prepared script, asked about their satisfaction with items such as function, comfort, and esthetics in addition to their overall satisfaction with the treatment they received. Data were analyzed with descriptive statistics., Results: The study revealed that 79% of participants were satisfied with their masticatory ability, 84% were satisfied with the comfort of the prosthesis, and 89% were satisfied with the esthetics of their new prosthesis. Additionally, 85% of participants reported satisfaction with the overall treatment experience, and 90% would recommend that a friend receive the same treatment., Conclusions: The results of this study support the incorporation of treatment with an implant-retained mandibular overdenture as part of the routine care provided in the predoctoral education program to meet the mandates of CODA., (Copyright © 2013 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)