Effect of a modified laminate veneer preparation design on absolute margin discrepancy and marginal overhang.

STATEMENT OF PROBLEM: Veneer preparation designs impact veneer accuracy. However, whether a modified design could reduce absolute margin discrepancy and marginal overhangs is unclear. PURPOSE: The purpose of this in vitro study was to investigate whether a modified veneer preparation design enhances the absolute margin discrepancy and marginal overhang. MATERIAL AND METHODS: The absolute margin discrepancy and the marginal overhang of 3 different veneer preparation designs on a typodont tooth (n=20): feather edge, shoulder, and shoulder with wings were measured. The feather edge design was prepared first and subsequently modified to create the shoulder and shoulder with wings preparations. Ceramic veneers were fabricated using computer-aided design and computer-aided manufacture with each veneer assessed for fit before cementation. Ten specimens were cut vertically, and 10 were cut horizontally in each group. The absolute margin discrepancy and marginal overhangs were measured for each cross-section with scanning electron microscopy. Descriptive data analysis and hypothesis testing were conducted using the nonparametric Kruskal Wallis test (α=.05). RESULTS: On the vertical sections, the shoulder with wings preparation had the best absolute margin discrepancy and overhang. The design was also best for mesial overhang and mesial absolute margin discrepancy when measuring horizontally. CONCLUSIONS: The shoulder with wings preparation design produced the smallest cervical absolute margin discrepancy and overhang. This design also produced absolute margin discrepancy and overhangs comparable with those of the shoulder design in the proximal areas.

Quality of cementing in hemiarthroplasty for elderly neck of femur fractures does not affect short term functional outcomes.

INTRODUCTION: Cemented hip hemiarthroplasty is a routine surgical option for elderly neck of femur (NOF) fractures. It is uncertain if quality of cementing has any effect on functional outcomes. The aim of this study was to determine if the quality of cementing would affect short term functional outcomes in elderly neck of femur fractures. MATERIALS AND METHODS: Retrospective analysis of 637 single-centre cemented hip hemiarthroplasties from 2014 to 2021 was performed. Each post-operative radiograph was double-read by 2 authors (1 resident and 1 fellowship trained surgeon) to determine quality of cementing via the Barrack grading. Disagreements were reviewed by a third reader. Cement grades were grouped as Optimal (Barrack grade A-B), or Suboptimal (Barrack grade C-D). Functional outcomes were compared using mobility (community- or home-ambulant), assistance required for mobility, and Modified Barthel Index (MBI). Surgical parameters were compared between the groups. RESULTS: There were 429 Optimal and 208 Suboptimal cases of cementing performed. There was no difference in age, American Society of Anesthesiologists score, mobility, assistance required, and MBI score pre-operatively (p > 0.05). Patients in the "Suboptimal" cementing group had a higher Charlson Comorbidity Index (CCI) score (p < 0.001). At 1 year post-operation, there was no significant difference between "Optimal" and "Suboptimal" cementing with regards to the proportion of community ambulators (30.2% vs. 25.7%, p = 0.252), walking independence (independent walkers (19.8% vs.17.3%), independent walkers with aids (41.3%vs.42.1%), walker with caregiver assistance (29.2%vs.33.7%), wheelchair-bound (9.6%vs.6.9%), p = 0.478), and distribution of MBI score (81.1%vs.82.2% achieving MBI > 60, p = 0.767). There was no significant difference in the proportion of patients with postoperative delirium (7.9% vs. 5.8, p = 0.324) or 1-year mortality rates (3.5% vs. 2.9%, p = 0.685). Except for stem design (12.2% tapered vs 20.1% collared; p = 0.011), no other surgical parameters were significantly different. The kappa value for inter-reader agreement was "substantial" at 0.727 (95% CI 0.682-0.772) (p < 0.001). CONCLUSION: Quality of cementing in cemented hip hemiarthroplasty for elderly NOF fractures does not affect the short-term functional outcomes. In low demand patients and patients at risk of BCIS, optimal cementing may not be necessary to achieve similar short-term functional outcomes. Further studies should be conducted to determine the effect of sub-optimal cementing on long-term functional outcomes.

Equivalent revision rates and patient reported outcomes with routine use of a short (125mm) cemented stem for total hip arthroplasty compared to a standard length (150mm) cemented stem. A two surgeon series of 1335 patients.

BACKGROUND: Routine total hip arthroplasty (THA) using a short cemented stem as compared with a standard length cemented stem may have benefits in terms of stress distribution, bone preservation, stem subsidence and ease of revision surgery. Two senior arthroplasty surgeons transitioned their routine femoral implant from a standard 150 mm Exeter V40 cemented stem to a short 125 mm Exeter V40 cemented stem for all patients over the course of several years. We analysed revision rates, adjusted survival, and PROMS scores for patients who received a standard stem and a short stem in routine THA. METHODS: All THAs performed by the two surgeons between January 2011 and December 2021 were included. All procedures were performed using either a 150 mm or 125 mm Exeter V40 stem. Demographic data, acetabular implant type, and outcome data including implant survival, reason for revision, and post-operative Oxford Hip Scores were obtained from the New Zealand Joint Registry (NZJR), and detailed survival analyses were performed. Primary outcome was revision for any reason. Reason for revision, including femoral or acetabular failure, and time to revision were also recorded. RESULTS: 1335 THAs were included. 516 using the 150 mm stem and 819 using the 125 mm stem. There were 4055.5 and 3227.8 component years analysed in the standard stem and short stem groups respectively due to a longer mean follow up in the 150 mm group. Patient reported outcomes were comparable across all groups. Revision rates were comparable between the standard 150 mm stem (0.44 revisions/100 component years) and the short 125 mm stem (0.56 revisions/100 component years) with no statistically significant difference found (p = 0.240). CONCLUSION: Routine use of a short 125 mm stem had no statistically significant impact on revision rate or PROMS scores when compared to a standard 150 mm stem. There may be benefits to routine use of a short cemented femoral implant.

Effect of cement spacer on fit accuracy and fracture strength of 3-unit and 4-unit zirconia frameworks.

BACKGROUND: Cement spacer is essential for compensating deformation of zirconia restoration after sintering shrinkage, allowing proper seating and better fracture resistance of the restoration. Studies assessing the effect of cement spacer on fit accuracy and fracture strength of zirconia frameworks are missing in the literature. Therefore, the aim of this study was to evaluate the effect of different cement spacer settings on fit accuracy and fracture strength of 3-unit and 4-unit zirconia frameworks. METHODS: Sixty standardized stainless-steel master dies were manufactured with 2 prepared abutments for fabricating 3-unit and 4-unit zirconia frameworks. The frameworks were assigned into 6 groups (n = 10) according to cement spacer setting (30 µm, 50 µm, and 80 µm) as follows: 3-unit frameworks; 3u-30, 3u-50, 3u-80, and 4-unit frameworks; 4u-30, 4u-50, and 4u-80. The frameworks were assessed for fit accuracy with the replica method. The specimens were cemented to their corresponding dies, and the fracture strength was measured in a universal testing machine. The Weibull parameters were calculated for the study groups and fractured specimens were inspected for failure mode. Two-Way ANOVA followed by Tukey test for pairwise comparison between study groups (α = 0.05). RESULTS: The cement spacer had a significant effect on both fit accuracy and fracture strength for 3-unit and 4-unit frameworks. The 50 µm spacer had significantly better fit accuracy followed by 80 µm, and 30 µm spacers. Both 50 µm and 80 µm spacers had similar fracture strength, and both had significantly better strength than 30 µm spacer. CONCLUSIONS: For both 3-unit and 4-unit zirconia frameworks, 50 µm cement spacer can be recommended over 30 µm and 80 µm spacers for significantly better fit accuracy and adequate fracture strength.

The effect of restorative material selection and cementation procedures on the durability of endocrowns in the anterior teeth: an in-vitro study.

OBJECTIVE: To investigate the fracture resistance and failure modalities of anterior endocrown restorations fabricated employing diverse ceramic materials, and bonded using various cementation methodologies. MATERIALS AND METHODS: Forty maxillary central incisors were divided into two main groups based on the ceramic materials used; GroupI (Zir): zirconia endocrwons (Zolid HT+, Ceramill, Amanngirrbach) and GroupII (E-Max): e-max endocrowns (IPS e.max CAD, Ivoclar Vivadent). Both groups were further split into two subgroups depending on the cementation protocols; subgroup IA "ZirMDP": endocowns cemented with MDP primer + MDP resin cement, subgroup IB (ZirNon-MDP): cemented with MDP primer + non-MDP resin cement, subgroup IIA (E-maxMDP): cemented with MDP primer + MDP resin cement, subgroup IIB (E-maxNon-MDP): cemented with MDP primer + non-MDP resin cement. (n = 10/subgroup). Endocrowns were manufactured using CAD/ CAM. Teeth were subjected to 10,000 thermal cycles. The fracture test was performed at 45o with a palatal force direction until the fracture occurred. Test results were recorded in Newton. The failure mode was examined using a stereomicroscope. A One-way ANOVA test was utilized to compare different groups regarding fracture strength values. Tukey`s Post Hoc was utilized for multiple comparisons. RESULTS: The comparative analysis of fracture strength across the diverse groups yielded non-significant differences, as indicated by a p-value exceeding 0.05. Nonetheless, an observable trend emerged regarding the mode of failure. Specifically, a statistically significant prevalence was noted in fractures localized within the endocrown/tooth complex below the cementoenamel junction (CEJ) across all groups, except for Group IIB, "E-max Non-MDP," where fractures within the endocrown/tooth complex occurred above the CEJ. CONCLUSIONS: Combining an MDP-based primer with an MDP-based resin cement did not result in a significant effect on the anterior endocrown fracture strength. CLINICAL RELEVANCE: Regardless of the presence of the MDP monomer in its composition, adhesive resin cement achieved highly successful fracture strength when used with MDP-based ceramic primers. Additionally, ceramic materials exhibiting elastic moduli surpassing those of dentin are discouraged due to their propensity to induce catastrophic fractures within the tooth structure.

A conservative approach to localize loose implant screw through cemented crown: an in vitro experimental study.

BACKGROUND: Retrieval of cement-retained implant-supported restorations is intriguing in cases of screw loosening. Detecting the estimated size of the screw access hole (SAH) could decrease destruction to the prosthesis and preserve the crown. OBJECTIVES: To precisely localize loose implant screws through cemented crowns to reduce crown damage after screw loosening. MATERIALS AND METHODS: In this in vitro study, 60 cement-retained implants supported 30 zirconia-based, and 30 ceramics fused to metal (CFM) lower molar crowns were invented, and each was subdivided into three subgroups (10 each). In group I (AI/BI) (control), SAH was created with the aid of orthopantomography (OPG). In contrast, in group II (zirconia-crown), SAH was created with the aid of CBCT + 3D printed surgical guide with a 2 mm metal sleeve in subgroups IIA/IIIA and CBCT + MAR was used to develop SAH in subgroups IIB/IIIB. SEM and Micro-CT scanned the SAH openings to determine the diameter of the hole, cracking, chipping, and chipping volume. RESULTS: Regarding the effect of plane CBCT and CBCT + MAR on prepared crowns, a highly significant association between group I with group II (p = 0.001) and group III (p = 0.002) was detected. Regarding the cracking of SAH, significant differences between the zirconium crown and CFM restoration (p = 0.009) were found, while for the chipping, no significant association was seen between groups (p = 0.19). CONCLUSIONS: CBCT, either as a plane CBCT or with MAR, significantly improved the accuracy of drilling the screw channel and decreased injury to the existing restoration and abutment, aiding in better localization of SAH in loosened implant abutment screws.

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

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

Clinical guidelines for posterior semidirect composite resin restorations: a case report with a 17-month follow-up.

Patients are always looking for conservative, esthetic, and long-lasting dental restorations, and the technique used directly influences the longevity of the treatment. The location of the restoration in the mouth and the extent of the decay influence the treatment choice. The larger the dimensions of the cavity preparation, the greater the difficulties in restoring the tooth using direct techniques. The semidirect technique, when indicated, can achieve satisfactory results. It is a relatively easy procedure, consisting of tooth preparation to receive an indirect restoration, fabrication of an alginate impression, fabrication of the composite resin restoration on a flexible cast, cementation, removal of excess cement, and occlusal adjustment. The aim of this case report is to present a viable alternative to direct and indirect restorations for posterior teeth with extensive decay. The article describes the extraoral semidirect technique for fabricating a composite resin restoration, highlighting its indications and discussing advantages and disadvantages.

Cemented is not superior to cementless total knee arthroplasty for complications: a propensity score matched analysis.

INTRODUCTION: There is continued debate regarding the survivorship and revision rate of cementless versus cemented total knee arthroplasty (TKA) prostheses. This includes the assessment of early revision surgery due to aseptic loosenings and periprosthetic joint infections (PJIs). Studies have not always taken into account the impact of comorbidities, such as diabetes, obesity, and tobacco. Therefore, we compared revisions in a large population of patients undergoing cemented or cementless TKAs at 90 days, 1 year, and 2 years. METHODS: A review of an administrative claims database was used to identify patients undergoing primary TKA, either cementless (n = 8,890) or cemented (n = 215,460), from October 1, 2015 to October 31, 2020. Revision surgery for PJI and aseptic loosening were identified with diagnosis and associated procedural codes at 90 days, 1 year, and 2 years and then compared between groups. A propensity matched-analysis was performed for age, sex, Charles Comorbidity Index (CCI) > 3, alcohol abuse, tobacco use, obesity, and diabetes. Chi square tests assessed statistical significance of differences in the matched cohorts using odds ratios (ORs) with 95% confidence intervals (CIs). A P < 0.05 was defined as statistically significant. RESULTS: Cementless TKA was associated with similar revisions rates due to PJIs at 90 days (OR, 1.04, 95% CI 0.79-1.38, p = 0.83), 1 year (OR, 0.93, 95% CI 0.75-1.14, p = 0.53, and 2 years (OR, 0.87, 95% CI 0.73-1.05, p = 0.17) in comparison to the cemented TKA cohort. The odds ratio of revision due to aseptic loosening was similar as well at 90 days (OR, 0.67, 95% CI 0.34-1.31, 0.31), 1 year (OR, 1.09, 95% CI 0.73-1.61, p = 0.76), and 2 years (OR, 1.00, 95% CI 0.73-1.61, p = 0.99). CONCLUSIONS: This study found a comparable risk of PJI and aseptic loosening in cementless and cemented TKA when controlling for several comorbidities, such as tobacco, diabetes, and alcohol. Therefore, with proper patient selection, cementless TKAs can be performed with expectation of low risks of infections and aseptic loosenings.

Periprosthetic fracture following arthroplasty for femoral neck fracture: is a cemented stem protective?

BACKGROUND: Periprosthetic femoral fractures (PFF) carry significant morbidity following arthroplasty for femoral neck fracture (FNF). This study assessed fracture complications following arthroplasty for FNF and the effect of cement fixation of the femoral component on intraoperative and post-operative PFF. METHODS: Between February 2014 and September 2021, 740 patients with a FNF who underwent arthroplasty were analyzed for demographics, surgical management, use of cement for fixation of the femoral component, and subsequent PFF. Variables were compared with Mann-Whitney or Chi-square as appropriate. Multivariate logistic regression was used to assess independent risk factors associated with intraoperative or post-operative PFF. RESULTS: There were 163 THAs (41% cemented) and 577 HAs (95% cemented). There were 28 PFFs (3.8%): 18 post-operative and 10 intraoperative. Fewer post-operative PFFs occurred with cemented stems (1.63% vs. 6.30%, p = 0.002). Mean time from surgery to presentation with post-operative PFF was 14 months (0-45 months). Mean follow-up time was 10.3 months (range: 0-75.7 months). In multivariate regression, use of cement and THA was independently associated with decreased post-operative PFF (cement: OR 0.112, 95% CI 0.036-0.352, p < 0.001 and THA: OR 0.249, 95% CI 0.064-0.961, p = 0.044). More intraoperative fractures occurred during THA (3.68% vs. 0.69%, p = 0.004) and non-cemented procedures (5.51% vs. 0.49%, p < 0.001). In multivariate regression, use of cement was protective against intraoperative fracture (OR 0.100, CI 0.017-0.571, p = 0.010). CONCLUSIONS: In patients with a FNF treated with arthroplasty, cementing the femoral component is associated with a lower risk of intraoperative and post-operative PFF. Choice of procedure may be based on patient factors and surgeon preference.

[Study on the pressure on ceramic veneers during cementation]. / Izuchenie velichiny davleniya na keramicheskie viniry vo vremya ikh tsementirovaniya.

OBJECTIVE: The aim of the study is measuring the magnitude and determining the method of finger pressure exerted by doctors on ceramic veneers during their fixation. MATERIAL AND METHODS: A simulation model was designed in order to measure the volume of finger pressure. Veneers were produced for 2 central incisors. Doctors alternately placed veneers on the model and applied pressure on them for 20 seconds simulating the clinical stage of cementing. The operator recorded the maximum readings of the scales and entered the result on the research protocol. In addition, it was recorded which finger the doctor exerts on the veneer during its cementing to ensure a tight fit: thumb or index finger. RESULTS: The values obtained during cementation of 54% doctors ranged up to 1 kg, 27% of doctors from 1 to 2 kg and only 19% more than 2 kg. 80% of doctors applied the main pressure on the veneer using their thumb, while the pressure force was 1.4 kg. For those doctors who pressed the veneer to the tooth with their index finger, the impact value was 0.8 kg. CONCLUSION: The finger pressure on the veneer during cementation applied by dentists varies, the average pressure on the veneers was about 1.5 kg. The amount of pressure on cement during laboratory tests of cements for fixing veneers differs from clinical values many times. The development of a veneers fixation protocol, taking into account the conducted research, will ensure a reliable and accurate fit of the veneer at the stage of its cementing.

Abutment margin levels and residual cement occurrence in cement-retained implant restorations: An observational study.

OBJECTIVES: To evaluate the association between different vertical levels of the abutment margin and residual cement prevalence in cement-retained implant restorations with customized abutments. METHODS: One hundred and nine single-unit cement-retained implant restorations with a screw-access channel were included. The crowns were intraorally cemented on the abutments, and excess cement was removed. The abutment-crown complex was unscrewed, and the abutment-crown complex and peri-implant tissue were photographed. Residual cement presence was recorded by dividing the abutment-crown complex and peri-implant tissue into four quadrants: mesial, distal, buccal, and lingual. The prevalence of residual cement was compared according to the height of the custom abutment margin of the corresponding quadrant. A multilevel model was used for statistical analysis (α = .05). RESULTS: Cement remnants were discovered on 72.48% of the dental implants. When the restoration quadrants were compared, cement remnants were present on 51.38%, 39.45%, 20.18%, and 17.43% of the mesial, distal, buccal, and lingual surfaces, respectively (p < .01). Regarding the abutment margin level, cement residues were found in 60.22% and 61.4% of the 0.5 mm subgingival and ≥1 mm subgingival margin groups, respectively, which were significantly more than those in the supragingival (23.65%) and equigingival (26.59%) margin groups (p < .01). After adjustment for confounding factors, the adjusted odds ratio (with 95% confidence interval) for residual cement in the subgingival margin groups was 3.664 (1.71, 7.852) when compared to the supragingival and equigingival margin groups. CONCLUSIONS: The risk of residual cement occurrence was 3.66-fold higher with a subgingival abutment margin than with supragingival and equigingival abutment margins.

Longevity of metal-ceramic single crowns cemented onto resin composite prosthetic cores with self-adhesive resin cement: an update of a prospective analysis with up to 106 months of follow-up.

OBJECTIVES: To evaluate the longevity of metal-ceramic single crowns cemented onto resin composite prosthetic cores using a self-adhesive resin cement in a prospective clinical descriptive study. METHODS: A total of 152 teeth were endodontically treated and received resin composite prosthetic cores and metal-ceramic crowns cemented with a self-adhesive resin cement. The patients included in the sample were recalled for clinical and radiography evaluation in an up-to-106-month period after the final cementation procedures, with an average of 62 months of follow-up. 91.5% of the sample (142 teeth) were evaluated regarding the treatment survival rate, analyzed considering the loss of crown retention (crown debonding) and tooth loss as the primary outcome. In addition, post debonding, and root fracture occurrences were also recorded as secondary outcomes to evaluate the success rate of the prosthetic treatment. The aesthetic parameters were also evaluated according to the FDI criteria. The Kaplan-Meier method and Cox regression with 95% confidence interval were applied for the statistical analysis. RESULTS: Regarding the primary outcome, the metal-ceramic crowns cemented with self-adhesive resin cement presented a high survival rate (91.5%), with 8 crown debondings and 3 tooth losses (1 due to caries and 2 due to periodontal disease) occurring after the evaluation period. For secondary outcomes, 9 root fractures and 4 post debondings occurred, generating a success rate of 72%. All crowns had a score 1 on the FDI criteria, indicating that they were clinically excellent or very good regarding the aesthetic parameters. CONCLUSION: The metal-ceramic crowns luted with a self-adhesive resin cement presented a survival rate of 91.5% after an average of 62 months of follow-up. Furthermore, the restorations remained aesthetically satisfactory over time, without changes that would indicate prosthetic retreatment. A success rate of 72% was obtained considering the secondary outcome, mainly related to intraradicular retainer failures (root fractures or post debonding). CLINICAL SIGNIFICANCE: The self-adhesive resin cement is clinically indicated for cementation of metal-ceramic crowns onto resin composite prosthetic cores.

Survival rate and treatment success of glass fiber posts cemented with two adhesive cementation strategies after up to 106 months: a randomized clinical trial.

OBJECTIVES: The objective of this study is to evaluate the longevity of two fiber post cementation strategies in a prospective, multicenter, non-inferiority, double-blind randomized controlled trial. METHODS: A total of 152 teeth, with adequate endodontic treatment and loss of coronal structure and bilateral simultaneous posterior occlusal contacts, were randomly allocated to receive glass fiber posts cemented with a conventional cementation strategy (CRC group: adhesive system + resin cement) (Adper Single Bond + RelyX ARC; 3 M-ESPE) or a self-adhesive cementation strategy (SRC group: self-adhesive resin cement; RelyX U100/U200; 3 M-ESPE). The patients were recalled annually for clinical and radiographical evaluation with a 93% recall rate (142 teeth, with 74 at CR groups and 68 at SRC group). The primary outcome was survival rate, considering the fiber post debonding (loss of retention). The secondary outcome included the success rate of the prosthetic treatment with crown debonding, post fracture, and tooth loss (not related to post failure). Both outcomes were evaluated annually. The Kaplan-Meier method and Cox regression with 95% confidence interval were used for the statistical analysis. RESULTS: For the primary outcome (failures directly related to fiber posts cementation strategy), there were 4 fiber post debondings (2 per group), 8 root fractures (3 for SRC group and 5 for CRC group), and one mixed failure (debonding combined with root fracture for CRC), with both strategies presenting similar survival rates (p = 0.331), with 88.9% for the CRC group and 90.9% for the SRC group. For the secondary outcome (failures not related to fiber post cementation strategies), there were 8 crown debondings, 3 post fractures, and 3 tooth losses, with no statistically difference between groups (p = 0.701), with 77% for SRC and 82% for CRC. CONCLUSION: Fiber post cementation strategies with conventional or self-adhesive resin cement presents similar tooth survival and success rates. TRIAL REGISTRATION: NCT01461239 CLINICAL RELEVANCE: Both adhesive cementation strategies led to high survival and success rates and are indicated for fiber post cementation, even after a long follow-up period (up to 106 months).

Impact of polyethylene glenoid cementation technique on cement mantle integrity and stability after cyclic loading: a computed tomography and biomechanical study.

BACKGROUND: There are no generally accepted guidelines for polyethylene (PE) glenoid component cementation techniques. In particular, it is not known whether the backside of a PE glenoid should be fully or partially cemented-or not cemented at all. We hypothesized that cementing techniques would have an impact on cement mantle volume and integrity, as well as biomechanical stability, measured as micromotion under cyclic loading. METHODS: To address our hypothesis, 3 different cementation techniques using a single 2-peg PE glenoid design with polyurethane foam were compared regarding (1) the quality and quantity of the cement mantle and (2) biomechanical stability after cyclic loading in vitro. Eight identically cemented glenoids per group were used. Group A underwent cement application only into the peg holes, group B received additional complete cement mantle application on the backside of the glenoid, and group C received the same treatment as group B but with additional standardized drill holes in the surface of the glenoid bone for extra cement interdigitation. All glenoids underwent cyclic edge loading by 105 cycles according to ASTM F2028-14. Before and after loading, cement mantle evaluation was performed by XtremeCT and biomechanical strength and loosening were evaluated by measuring the relative motion of the implants. RESULTS: The cement mantle at the back of the implant was incomplete in group A as compared with groups B and C, in which the complete PE backside was covered with a homogeneous cement mantle. The cement mantle was thickest in group C, followed by group B (P = .006) and group A (P < .001). We did not detect any breakage of the cement mantle in any of the 3 groups after testing. Primary stability during cyclic loading was similar in all groups after the "running-in" phase (up to 4000 cycles). Gross loosening did not occur in any implant. CONCLUSIONS: Coverage of the PE glenoid with cement was reproducible in the fully cemented groups (ie, groups B and C) as compared with relevant cement defects in group A. The addition of cement to the back of the PE glenoid and additional drill holes in the glenoid surface did not improve primary stability in the tested setting.

Are There More Radiolucent Lines in Patients Who Underwent Total Knee Arthroplasty With or Without a Tourniquet During Cementation at 5 to 8 Years After Surgery?

BACKGROUND: This study investigated the presence and progression of radiolucent lines (RLLs) after cemented total knee arthroplasty (TKA) with or without tourniquet use. METHODS: There were 369 consecutive primary cemented TKAs with 5 to 8 years of follow-up. A tourniquet was used during component cementation in patients who underwent surgery from January 3, 2006, to March 31, 2010. No tourniquet was used from August 14, 2009, to October 14, 2014. There were 192 patients in the tourniquet group (TQ) and 177 patients in the no tourniquet group (NQ). Patient demographics, reoperations, and complications were recorded. RLLs were identified on anteroposterior, lateral, and skyline x-rays at 1, 2, and 5 to 8 years postoperatively using the modern knee society radiographic evaluation system. Demographics, reoperations, complications, and RLLs were compared. Age, sex, and body mass index were similar between groups. Mean tourniquet time in TQ was 11 minutes (range, 8 to 25). RESULTS: The presence of RLLs differed between groups, with 65% of TQ knees having RLLs under any part of the prostheses versus 46% of NQ knees (P < .001). The progression of RLL >2 mm occurred in 26.0% of knees in TQ and 16.7% of knees in NQ (P = .028). There were 13 TKAs that underwent subsequent revision surgery. There was no statistically or clinically significant difference in revision rate between groups (7 revisions in TQ, 6 in NQ, P = .66). CONCLUSION: Less RLLs were identified in NQ versus TQ. There were no statistically or clinically significant differences in revision rates between the NQ and TQ groups at 5 to 8 years.

Trends in Total Knee Arthroplasty Cementing Technique Among Arthroplasty Surgeons-A Survey of the American Association of Hip and Knee Surgeons Members.

BACKGROUND: Aseptic loosening persists as one of the leading causes of failure following cemented primary total knee arthroplasty (TKA). Cement technique may impact implant fixation. We hypothesized that there is variability in TKA cement technique among arthroplasty surgeons. METHODS: A 28-question survey regarding variables in surgeons' preferred TKA cementation technique was distributed to 2,791 current American Association of Hip and Knee Surgeons (AAHKS) members with a response rate of 30.8% (903 respondents). Patterns of responses were analyzed by grouping respondents by their answers to certain questions including cementing technique, tibial cement location, and femoral cement location. RESULTS: A total of 73.5% reported performing at least 7 of 8 of the highest consensus techniques, including vacuum mixing (79.9%), using two bags (76.1%), tibial implant first (95.2%), single-stage cementing (96.9%), compression of the implants in extension (91.7%), and use of a tourniquet (84.3%). Medium and high viscosity cement was most commonly used (37.9 and 37.8%, respectively). Finger pressurization was most common (76.1%) compared to a gun (29.8%). There were 26.5% of respondents performing 6 or fewer of the most common majority techniques and seemed to perform other less common techniques (eg, use of a single bag of cement, trialing or closure prior to cement curing, and heating to accelerate cement curing). Cement was most commonly applied to the entire bone and implant surface on both the tibia (46.4%) and femur (47.7%), leaving much variation in the remaining cement application location responses. DISCUSSION: There appears to be variability in cemented TKA technique among arthroplasty surgeons. There were 26.5% of respondents performing less of the majority techniques and also performed other additional low-response rate techniques. Further studies that look at the impacts of variation in techniques on outcomes may be warranted. Our study demonstrates the need for defining best practices for cement technique given the substantial variability identified.

Direct Cementation of Dual Mobility Cups Into the Bony Acetabulum in Primary Total Hip Arthroplasty: Clinical and Radiographic Outcomes at a Minimum 5-Year Follow-Up.

BACKGROUND: Cemented dual mobility cups (DMCs) are commonly used in combination with acetabular reinforcement devices. Indeed, according to literature, direct cementation of metal-backed acetabular components into the bony acetabulum remains controversial as this technique is potentially associated with increased rates of aseptic loosening. Therefore, this study aimed to evaluate the clinical and radiographic outcomes of DMC cemented into the bony acetabulum in primary total hip arthroplasty (THA). METHODS: A total of 49 THA (48 patients, mean age 78 years [range, 51 to 91]) performed with direct cementation of a DMC into the bony acetabulum were prospectively included in our total joint registry and retrospectively reviewed. The clinical outcome was assessed using the Harris hip score (HHS). The radiographic outcome included measurement of component positioning and occurrence and progression of demarcation around the cemented DMC. Complications were reported with a particular attention to cemented fixation failure and aseptic loosening. RESULTS: At a 7-year mean follow-up (range, 5 to 8), the pre-to postoperative HHS improved from 47 (range, 30 to 58) to 92 points (range, 80 to 98) (P < .01). Nonprogressive and focalized demarcations were observed in 7 THA (14%). Importantly, no progressive demarcation or DMC aseptic loosening was observed. CONCLUSION: Direct cementation of DMC into the bony acetabulum ensured a stable fixation with no progressive demarcation or aseptic loosening at midterm follow-up. Therefore, this technique can be selectively considered in primary THA, especially in elderly or frail patients to avoid potential mechanical failure of press-fit fixation due to altered bone quality or additional morbidity related to the use of acetabular reinforcement devices.

Clinical evaluation of zirconia crowns cemented with two different resin cements: A retrospective study.

BACKGROUND: Self-adhesive resin cement has been used extensively with zirconia crowns. Several in vitro studies showed that adhesive resin cementation may increase zirconia crowns' retention and their fatigue resistance. OBJECTIVES: This retrospective study aimed to evaluate the clinical performance, survival and success rates and complications encountered with zirconia crowns cemented with two different self-adhesive resin cements. METHODS: A total of 112 patients who received 176 monolithic zirconia crowns were evaluated. Crowns were cemented with RelyX Unicem 2 (n = 74) and Panavia SA (n = 102) self-adhesive resin cements. Clinical assessments of the crowns and supporting periodontal structures were performed following the modified California Dental Association (CDA) criteria. Intraoral photographs and periapical and bitewing radiographs were obtained for further assessment by two evaluators. Descriptive statistics, McNemar, t-test, log rank (Mantel-Cox) tests and Kaplan-Meier survival analyses were performed (a = .05). RESULTS: The 5-year survival and success rates were 100% and 96.4%, respectively. The complications encountered were recurrent caries (2.2%) and the need for endodontic treatment (0.5%). No technical complications, such as fracture or loss of retention, were observed. The type of cement and patient-related factors did not influence the survival and success rates of the crowns. CONCLUSIONS: Survival rate of zirconia crowns cemented with two different self-adhesive resin cements was 100% after 5 years.

Selective adhesive luting: A novel technique for improving adhesion achieved by universal resin cements.

OBJECTIVE: We aimed to introduce the concept of "Selective adhesive luting-SAL" which is explained through clinical steps and supported by preliminary laboratory evidence. CLINICAL CONSIDERATIONS: Cementation with rubber dam is difficult to perform in case of short abutment teeth and/or subgingival crown margins. By means of universal resin cements/universal adhesive systems, which can be employed in self-adhesive as well as adhesive luting procedures, this paper presents a novel technique allowing clinicians to perform reliable cementation where rubber dam isolation is difficult. The SAL technique entails the application of a universal adhesive system only on easily accessible abutment surfaces, enabling simultaneous adhesive and self-adhesive luting in different portions of the abutment. The SAL clinical workflow is explained through prosthodontic rehabilitation of maxillary right central incisor affected by microdontia and restored with a lithium-disilicate crown. Furthermore, our laboratory microshear bond strength study supports the rationale behind SAL application demonstrating higher bond strength even when the adhesive resin is placed only on one portion of the cementation substrate. CLINICAL SIGNIFICANCE: This article advocates the application of SAL technique in clinical situations where effective adhesive luting is uncertain, since it can improve the adhesion between the tooth and universal resin cements.