Effect of Varying Layers of Two Die Spacers on Precementation Space of Full Coverage Restorations.

The purpose of this study was to evaluate and compare the effect of varying layers of two commercially available die spacers on pre-cementation space of full coverage restorations in vitro and in vivo. Seven dies were prepared for each of 15 subjects. On three dies 1, 2, 3 layers of Pico-fit and on other three dies 1, 2, 3 layers of Yeti die spacers applied, wax pattern fabricated, invested and cast. Metal copings seated in vitro on die without die spacer and on prepared tooth of respective subject with fit-checker. Thickness of fit checker was measured using micrometer at mid-axial, mid-occlusal and near finish line locations that provided pre-cementation space. Result of ANOVA tests suggested significant difference among groups with varying layers. There was no significant difference between pre-cementation space achieved with Pico-fit and Yeti die spacers. The r values suggested positive correlation between the respective pair of in vivo and in vitro groups. (1) There was significant difference between pre-cementation space at mid-axial and mid-occlusal sites achieved with 1, 2 and 3 layers of die spacers except between 1 and 2 layers and 1 and 3 layers at mid-occlusal site. (2) Pre-cementation space achieved with Pico-fit and Yeti die spacers did not differ significantly for same location, layers and in vitro and in vivo. (3) Pre-cementation space achieved in vitro was analogous to pre-cementation space achieved in vivo for respective location, layers and die spacer.

Comparative study of shade matching performance of dental students under natural daylight and daylight lamp conditions.

BACKGROUND: As visual shade matching is subject to light source variables, this study was conducted to compare shade matching performance of dental students under two lighting conditions, ie, natural daylight and a commercially available daylight lamp. MATERIALS AND METHODS: Two sets of porcelain discs were prepared. The first set consisted of eight porcelain discs of shades A2, A3, A3.5, B2, B3, C2, C3, and D3 of the Vitapan Classical Shade Guide system. The second set consisted of three porcelain discs of shade A2, B2, and C2, having exactly similar L*a*b* values to those of the corresponding shade discs in the first set. Forty dental students were asked to find the closest match for the shades A2, B2, and C2 in the second set from the first set under natural daylight and daylight lamp conditions. The average ΔE between the presented and selected shade was calculated for each participant under the two lighting conditions. The significance was statistically assessed using a paired t test. RESULTS: The average ΔE between presented and selected shade for individual participants under natural daylight ranged from 0 to 4.84, with a mean of 2.24, while those under daylight lamp conditions ranged from 0 to 3.68, with a mean of 1.14. The difference was statistically significant, with P < 0.0001. CONCLUSION: Daylight lamp conditions significantly improved the shade matching performance of dental students.

A simplified chair-side remount technique using customized mounting platforms.

Correct occlusal relationships are part of the successful prosthetic treatment for edentulous patients. Fabrication of complete dentures comprises of clinical and laboratory procedures that should be executed accurately for achieving success with fabricated dentures. Errors occurring during the clinical and laboratory procedures of a denture may subsequently lead to the occlusal errors in the final prosthesis. These occlusal errors can be corrected in two ways: i) in patient's mouth ii) by recording new centric relation and remounting dentures on an articulator. The latter method is more feasible because the mobility of denture base on the mucosa in oral cavity does not permit the identification of premature contacts in centric occlusion and tooth guided eccentric excursions. This article describes a modest and effective clinical chair-side remount procedure using customized mounting platforms.

Ten-yr renal allograft survival of patients with antiphospholipid antibody syndrome.

BACKGROUND: Long-term allograft survival of antiphospholipid antibody syndrome (APAS) patients as well as patients who have antiphospholipid antibodies but no thrombotic complications remains largely unknown. This study evaluates long-term allograft survival of APA as well as patients with APAS. METHODS: During the study period from January 1, 1992 through May 31, 2009, 1625 patients with ESRD awaiting renal transplants were screened for APAS. Ninety-four (5.8%) of these patients had circulating levels of anticardiolipin antibodies (ACA) and 39 of these patients had documented evidence of clotting disorders and were diagnosed with APAS. Twenty-one patients with APAS received transplants on either low molecular weight (LMW) heparin or Coumadin as anticoagulation therapy. Of 94 patients with only ACA, 46 received renal transplants. Of the remaining 1492 patients, 1285 patients with no evidence of either ACA or APAS received renal transplants. RESULTS: Ten-yr allograft survival of patients with APAS treated with Coumadin was similar to those treated with LMW heparin (18% vs. 20%, NS). However, those allograft survivals were significantly lower than those patients positive for ACA (28%) alone (ACA vs. LMW heparin or Coumadin p=0.0001). CONCLUSION: Despite anticoagulation therapies, patients with APAS have lower long-term graft survival than those patients who have circulating ACA but no APAS.

Functional and esthetic rehabilitation of mutilated dentition associated with amelogenesis imperfecta.

This clinical case report describes the oral rehabilitation of an adult female patient diagnosed with hypoplastic amelogenesis imperfecta with inadequate, deteriorated restorations of anterior teeth, inadequate clinical crown heights of posterior teeth due to severe attrition of hypoplastic enamel. Treatment included extraction of teeth with poor prognosis, root canal treatment and crown lengthening of severely worn out teeth & full coverage porcelain-fused-to metal fixed restoration of entire dentition. The main objectives of the selected treatment were to enhance the esthetics, restore masticatory function and eliminate the teeth sensitivity. These treatment objectives were successfully met by sequential fixed prosthodontics treatment using Pankey-Mann-Schuyler philosophy of complete occlusal rehabilitation. Treatment not only restored function and esthetic, but also showed a positive psychological impact and thereby improved perceived quality of life.

Comparison of effect of desensitizing agents on the retention of crowns cemented with luting agents: an in vitro study

PURPOSE: Many dentists use desensitizing agents to prevent hypersensitivity. This study compared and evaluated the effect of two desensitizing agents on the retention of cast crowns when cemented with various luting agents. MATERIALS AND METHODS: Ninety freshly extracted human molars were prepared with flat occlusal surface, 6 degree taper and approximately 4 mm axial length. The prepared specimens were divided into 3 groups and each group is further divided into 3 subgroups. Desensitizing agents used were GC Tooth Mousse and GLUMA(R) desensitizer. Cementing agents used were zinc phosphate, glass ionomer and resin modified glass ionomer cement. Individual crowns with loop were made from base metal alloy. Desensitizing agents were applied before cementation of crowns except for control group. Under tensional force the crowns were removed using an automated universal testing machine. Statistical analysis included one-way ANOVA followed by Turkey-Kramer post hoc test at a preset alpha of 0.05. RESULTS: Resin modified glass ionomer cement exhibited the highest retentive strength and all dentin treatments resulted in significantly different retentive values (In Kg.): GLUMA (49.02 +/- 3.32) > Control (48.61 +/- 3.54) > Tooth mousse (48.34 +/- 2.94). Retentive strength for glass ionomer cement were GLUMA (41.14 +/- 2.42) > Tooth mousse (40.32 +/- 3.89) > Control (39.09 +/- 2.80). For zinc phosphate cement the retentive strength were lowest GLUMA (27.92 +/- 3.20) > Control (27.69 +/- 3.39) > Tooth mousse (25.27 +/- 4.60). CONCLUSION: The use of GLUMA(R) desensitizer has no effect on crown retention. GC Tooth Mousse does not affect the retentive ability of glass ionomer and resin modified glass ionomer cement, but it decreases the retentive ability of zinc phosphate cement.

Transplantation of high panel-reactive antibody left ventricular assist device patients without crossmatch using on-bypass pheresis and alemtuzumab.

BACKGROUND: Highly sensitized (HS) left ventricular assist device (LVAD) patients with high panel-reactive antibody (PRA) levels present a challenge. Alemtuzumab, a potent depleting agent for T and B lymphocytes (months to years), and plasmapheresis, offer an opportunity for heart transplantation to these patients who might die of VAD complications on the transplant waiting list. This study compared rates of acute rejection and survival of a HS LVAD cohort with a contemporaneous control group after heart transplant. METHODS: Clinical courses of 31 consecutive patients who underwent transplantation between January 2006 and January 2011 were reviewed. Eight patients with a T or B PRA of 70 or more (HS+) received non-crossmatched, ABO-compatible hearts using intraoperative plasmapheresis and alemtuzumab induction. Controls (HS-) received basiliximab induction. Acute rejection was defined as International Society for Heart and Lung Transplantation grades 2R or higher, or antibody-mediated rejection. RESULTS: The difference in survival between HS+ and HS- groups at 1 year (100% vs 94%) or at a mean follow-up of 2.3 and 2.4 years (75% vs 70%) was not significant. Retrospective lymphocytotoxic crossmatches were positive in 7 of 8 HS+ patients (6 T+ and B+, 1 B+) vs none in the HS- group (p < 0.001). There was a trend toward increased risk of cellular rejection per 100 patient-days beyond 1 year in the HS+ group (p = 0.07). Risk of humoral rejection was significantly increased in the HS+ group (38% vs 4%; p = 0.04). CONCLUSIONS: Heart transplantation with plasmapheresis and alemtuzumab in HS LVAD patients, most with a positive crossmatch, does not compromise midterm survival. The expected higher rates of rejection, especially beyond the first postoperative year, demand adjustments in surveillance strategies and immunosuppressive management.

Peri-operative alemtuzumab (Campath-1H) and plasmapheresis for high-PRA positive lymphocyte crossmatch heart transplant: a strategy to shorten left ventricular assist device support.

Patients on a left ventricular assist device (LVAD) often have a high level of panel-reactive antibodies (PRA). Conventional therapy is to await a heart from a negative prospective-crossmatch donor. We transplanted three high-PRA patients with non-crossmatched hearts, using intra- and post-operative plasmapheresis and long-term T-/B-/plasma-cell therapy with alemtuzumab. Three highly sensitized patients (70%, 94% and 96% T-PRA; 63%, 24% and 73% B-PRA) were transplanted after 29, 187 and 94 days LVAD support. The first patient (Case 1) had an erroneous prospective negative crossmatch (due to an outside laboratory's use of the wrong patient's serum) with immediate allograft dysfunction. The correct serum showed a strongly positive crossmatch; plasmapheresis followed by alemtuzumab (20 mg intravenously) shortly after arrival in the ICU resulted in rapid hemodynamic improvement. Encouraged by this success, the next two patients (Cases 2 and 3) underwent LVAD explant and heart transplant with the next available ABO-identical, non-crossmatched donors, using plasmapheresis on bypass immediately before heart implant and alemtuzumab 20 mg intravenously upon ICU arrival, with uneventful courses. All three patients had positive retrospective T- and B-cell crossmatches. Maintenance immunosuppression consisted of cyclosporine and routine prednisone taper, with plasmapheresis as needed (Patient 1, x10; Patient 2, x5) based on diastolic dysfunction. Mycophenolate mofetil was started as a third agent several months post-transplant. Patients are presently New York Heart Association (NYHA) Class I at 26, 16 and 13 months post-transplant. In this small series with follow-up, immediate antibody removal with plasmapheresis, combined with alemtuzumab, a long-acting antibody to CD52 (expressed on T, B and some plasma cells), appears effective in allowing transplantation in sensitized, positive crossmatch recipients. Expanded use of this strategy could shorten LVAD support in many sensitized patients.

Clinical importance of anti-human leukocyte antigen-specific antibody concentration in performing calculated panel reactive antibody and virtual crossmatches.

BACKGROUND: Highly sensitized patients develop multi-human leukocyte antigen (HLA) specific antibodies. This study measures concentrations of anti-HLA antibodies in multispecific sera by converting fluorescence intensity into molecules of equivalent soluble fluorochrome (MESF) units. This was used to determine MESF units required for a positive T and B flow crossmatches (FLXM). METHODS: MESF values of negative controls and sera from patients devoid of HLA antibodies were measured by FLXM and flow panel reactive antibody (PRA) screening beads. Fluorescence intensity values of anti-HLA specific antibodies determined by FlowPRA single antigen beads of highly sensitized patients were converted into MESF units. In addition, endpoint titers, MESF units, and % PRA of 26 sera were established. RESULTS: MESF analysis accurately predicted the outcomes of 100% of T and B FLXM of sera with strong (MESF units>18,000) donor-specific antibody (DSA). The predictive values of T and B FLXM declined to 95% and 88% with weak DSA (6,000 MESF<10,000). Endpoint titers of sera from highly sensitized patients ranged from 1:512 to 1:8 with corresponding MESF values of 452,596 to 20,000 units. However, there was no statistical difference in PRA values among these sera (95%-100%). We successfully transplanted five patients who had weak donor-specific HLA antibodies (MESF units>2,000). The graft survival at 1 year was 100% and there was no evidence of DSA posttransplant. CONCLUSION: MESF analysis is both a time and cost efficient way of measuring antibody strength. The strength of the antibody present in the sera of transplant candidates is critical for crossmatch prediction.

Alemtuzumab (Campath 1H) induction with tacrolimus monotherapy is safe for high immunological risk renal transplantation.

Immunosuppression for immunologically high-risk renal transplant patients usually involves antithymocyte globulin induction with triple drug maintenance therapy. Alemtuzumab, a humanized anti-CD52 antibody, has shown promise in tolerogenic induction protocols, requiring minimal maintenance immunosuppression. In this prospective, open-label, randomized, controlled trial, we enrolled 21 high immunological risk patients (i.e., panel reactive antibody>20% or previous transplant). Patients received either single-dose alemtuzumab given before graft reperfusion, with tacrolimus monotherapy, or four doses of Thymoglobulin with tacrolimus, mycophenolate, and steroids. Median follow-up was 377 days. One patient in the Thymoglobulin group who suffered primary graft nonfunction died. One-year cumulative graft survival was 85.7% for the alemtuzumab group and 87.5% for the Thymoglobulin group. Two alemtuzumab and three Thymoglobulin patients suffered rejection episodes. Infection rates were similar. Early results of this ongoing study indicate that a tolerogenic protocol with alemtuzumab induction and tacrolimus maintenance monotherapy is safe in immunologically high-risk renal transplant patients.

DP reactive antibody in a zero mismatch renal transplant pair.

This study describes molecular basis for positive B-cell flow crossmatch in a zero mismatch (0MM) transplant pair. Our end-stage renal disease patient was B-cell flow crossmatch positive with a 0MM deceased donor. DNA from the donor and patient were further typed by a high-resolution method. The patient's sera were tested for anti-HLA reactivity by single antigen bead using a Luminex platform. The patient and donor were found to be HLA identical except for a single DP allele MM (DPB1*0601). As there was no single antigen bead coated with DPB*0601, analysis of the amino acid residues of reactive and nonreactive DPB1 alleles was conducted. The results showed that all reactive alleles carried the amino acid D-E at residue 55 and 56 of DPB1. The MM allele DPB1*0601 also carries the DE 55-56 epitope. We conclude that positive B-cell flow crossmatch was likely the result of single MM in the DP locus.

Prediction of crossmatch outcome of highly sensitized patients by single and/or multiple antigen bead luminex assay.

BACKGROUND: We used a solid-phase assay to identify human leukocyte antigen (HLA) Class I and II specificities in highly reactive sera, and applied this information to predict crossmatch outcome with greater than 90% accuracy. METHODS: Sera from 20 highly sensitized end-stage renal disease patients reactive to 70-100% of HLA Class I and II antigen panel were analyzed by single and/or multiple antigen flow microparticle bead assay using Luminex platform (Luminex assay). These sera contained antibodies directed against high frequency public HLA class I and/or II epitopes accounting for 70-100% of serum's total reactivity. More than 2,000 complement dependent cytotoxicity (CDC) and 200 flow crossmatches (FLXM) were performed using sera from these patients and deceased donor T and B lymphocytes. RESULTS: Luminex serum analysis was able to correctly predict outcomes of 95% of T and B cell FLXM. In contrast, predictive values for the CDC T and B cell crossmatches by Luminex serum analysis were only 77% and 75%, respectively. The use of serum analysis in donor selection would have reduced the total number of required FLXM by more than 50%. The frequency of negative T cell FLXM was 56% when donors were selected randomly; however, if serum antibody analysis had been used to preselect the donors by excluding donors that were likely to be positive, the frequency of corresponding negative crossmatches would have increased up to 93%. CONCLUSION: This approach to donor selection may allow wider geographic sharing of cadaver donor organs without actually performing the crossmatch.

Soluble CD30 concentrations in ESRD patients with and without panel reactive HLA antibodies.

BACKGROUND: In this retrospective study we compared accuracy of panel reactive antibodies (PRA) with serum soluble CD30 (sCD30) contents in predicting acute rejection crisis post-renal transplant. METHODS: Pre-transplant sera from 115 patients were evaluated for their PRA and sCD30 concentrations. All patients received calcineurin inhibitor-based immunosuppressive therapy. Objective measurements for rejection were biopsy-proven acute rejection (AR) episodes within first six months of the transplant. Post-transplant sera of patients with AR were tested for the presence of donor-specific HLA antibodies (DSA). RESULTS: Overall AR rate was 16% (18/115). Patients positive for PRA and sCD30 tests were at significantly higher risk for AVR compared with those patients negative for both the tests (36% vs. 5%, p=0.01). Among negative PRA patients risk for AR was significantly elevated if they were also tested positive for sCD30 concentrations (21% vs. 5%, p=0.04). Of the 18 patients with AR, 14 were positive for sCD30, and 13 of them (93%) developed DSA post-transplant (p=0.001). CONCLUSION: These data showed that patients positive for sCD30 contents are at high risk for the development of DSA and AR post-transplant regardless of their pre-transplant PRA.

Pretransplant soluble CD30 is a better predictor of posttransplant development of donor-specific antibodies and acute vascular rejection than panel reactive antibodies.

BACKGROUND: This study tests a hypothesis that pretransplant concentration of soluble CD30 (sCD30) is a better predictor of posttransplant development of donor-specific HLA antibodies (DSA) and acute vascular rejection (AVR) than panel reactive HLA antibodies (PRA). METHODS: Pretransplant sera from 115 patients were evaluated for their PRA and sCD30 concentrations. All patients received calcineurin-inhibitor based immunosuppressive therapy. Objective measurements for rejection were biopsy-proven AVR episodes within first 6 months of the transplant. Posttransplant sera of patients with or without AVR were tested for the presence of DSA. RESULTS: AVR rate was 16% (18/115). Patients positive for PRA and sCD30 tests were at significantly higher risk for AVR compared to those patients negative for both tests (36% versus 5%, p = 0.01). Among negative PRA patients risk for AR was significantly elevated if they were also tested positive for sCD30 concentrations (21% versus 5%, p = 0.04). Of the 18 patients with AVR, 14 were positive for sCD30, and 13 of them (93%) developed DSA posttransplant (p = 0.001) Nineteen patients without AVR were tested for DSA and sCD30 concentrations. Only two of these 19 patients were positive for sCD30 and DSA. AVR was strongly associated with the patients tested positive for both the tests: DSA and sCD30 (p = 0.00007). Furthermore, patients with AVR are more likely to produce DSA than those without AVR (p = 0.02). CONCLUSION: These data support our hypothesis that patients positive for sCD30 contents are at high risk the development of DSA and AVR posttransplant regardless of their pretransplant PRA.

Campath and renal transplant rejection.

No clear guidelines exist for the treatment of acute vascular rejection following renal transplantation. This report documents one patient who was treated with plasmapheresis, immunoglobulin and Campath with good initial response. However, rejection recurred resulting in graft loss and, in addition, the patient developed post-transplant lymphoma.

Efficacy of anticoagulation therapy in end-stage renal disease patients with antiphospholipid antibody syndrome.

BACKGROUND: End-stage renal disease (ESRD) patients with antiphospholipid antibody syndrome (APAS) remain at high risk for the development of renal thrombosis without the benefit of anticoagulation therapy. This study examines the efficacy of anticoagulation therapy in this high-risk patient population. METHOD: Of nine APAS renal-transplant patients, seven were treated with coumadin, whereas two were treated with heparin. RESULTS: Of the two patients treated with heparin, one had early allograft loss, whereas the other patient is doing fine at 5 years posttransplant. Of the seven 7 patients treated with coumadin, two patients are doing well at 2 and 3 years posttransplant, two had early allograft loss, the remaining three patients returned to dialysis after they were taken off of the coumadin at 6, 12, and 20 months posttransplant because of bleeding complications. CONCLUSIONS: Anticoagulation therapy is beneficial to some but not all APAS patients. In addition, bleeding complications are a serious side effect of this therapy.