Comparison of morbidity at the donor site and clinical efficacy at the recipient site between two different connective tissue graft harvesting techniques from the palate: A randomized clinical trial

Background

This study was conducted to compare the pain levels in patients and the clinical efficacy of grafts obtained using two techniques, namely de-epithelialized gingival graft (DGG) and subepithelial connective tissue graft (SCTG), in combination with coronally advanced flap (CAF) for the treatment of multiple adjacent gingival recessions.

Methods

Twelve patients were treated using DGG+CAF on one side and SCTG+CAF on the other. The patients' pain levels at the surgical site, the number of analgesics taken on days 3 and 7, the mean root coverage (MRC), the percentage of complete root coverage (CRC), color match, and gingival thickness (GT) at the graft recipient site were evaluated 6 months after surgery.

Results

The total number of analgesics taken during the 7-day period after surgery and pain levels at the surgical site from day 3 to day 7 were significantly higher in the DGG+CAF group compared to the SCTG+CAF group (P=0.001). In the 6-month follow-up, color match and CRC were significantly higher in the SCTG+CAF group, while GT was significantly higher in the DGG+CAF group. There was no significant difference in MRC between the two groups.

Conclusion

The pain and analgesic consumption levels were higher in the DGG+CAF group compared to the SCTG+CAF group, and the recipient site had a weaker color match. However, this technique can lead to a greater increase in the thickness of the grafted area.

Comparison of Ridge Mapping and Cone Beam Computed Tomography for the Determination of Alveolar Ridge Width

Objective

This study aimed to evaluate the accuracy of cone beam computed tomography (CBCT) and ridge mapping for linear measurement of alveolar ridge width.

Materials and methods

In this cross-sectional study, 25 implant placement sites in 25 patients were selected and an acrylic stent was fabricated for each one. Three buccal-lingual point pairs were located on the stent at 4-, 7-, and 10-mm distances from the soft tissue summit of the alveolar ridge. The measurements were recorded by three examiners (two periodontists and one radiologist).

Results

Both techniques (CBCT and ridge mapping) overestimated alveolar ridge width compared to direct measurements, but mean differences compared to direct measurements (gold standard) were not statistically significant. The lowest mean difference compared to direct measurements was related to the ridge mapping technique, and CBCT measurements were less accurate to measure the alveolar ridge width.

Conclusion

In determining alveolar ridge width, ridge mapping and CBCT are both valid and useful. Ridge mapping provides high accuracy, simplicity, and lack of radiation exposure.

Dimensional changes of keratinized mucosa after accordion versus conventional free gingival graft around dental implants: A randomized two-arm parallel clinical trial

OBJECTIVES

Free gingival graft (FGG) is the most effective way to increase the apico-coronal width of the keratinized mucosa. In case of limited donor tissue, the accordion technique can be used. This study compared FGG for dimensional and clinical changes using accordion and conventional methods.

MATERIALS AND METHODS

Ninety-four implants with keratinized tissue deficiency (< 2mm) were randomly assigned to treatment with accordion (49 implants) and conventional (45 implants) FGG. Endpoints including apico-coronal keratinized tissue width, vertical shrinkage, vestibular depth, probing depth, bleeding on probing, and plaque index were measured. The graft harvesting and recipient bed preparation method were similar in the two groups, and the only difference was the graft length. FGG was harvested with a length 40% shorter than the mesiodistal length of the recipient area in the accordion method and as much as the recipient area in the conventional method.

RESULTS

vertical graft shrinkage 1, 3 and 6 months following conventional graft placement was 12.04±14.99, 17.12±20.40, 23.29±24.63 percent, respectively. In the accordion graft group, the shrinkage was significantly greater with 30.10±16.12, 36.99±15.51, 43.75±18.78 percent at 1, 3 and 6 months, respectively (p-Value<0.001). Other factors did not show a clinically significant difference between the two groups.

CONCLUSIONS

Comparison of vertical shrinkage changes shows that the shrinkage rate in the accordion group is significantly higher than the conventional group.

Evaluation of topical erythropoietin application on the healing outcome of gingival graft recipient site; a randomized controlled clinical trial

Background

Free gingival graft (FGG) is a highly predictable method to increase the width of keratinized gingiva. Various materials have been reported to accelerate the wound healing process. Considering the positive effect of EPO on dermal wound healing this study aimed to investigate the effects of EPO on the rate of healing and degree of inflammation in free gingival grafts.

Methods

Seventeen patients with bilateral lack of keratinized gingiva in mandible were selected for this clinical trial. The surgical intervention was performed after phase I periodontal therapy.

Recipient site was prepared apical to the mucogingival line, and FGG was harvested from the palate. Before graft placement, the test side and control side were treated with 1 ml of EPO 4000 IU/ml and distilled water, respectively, for 2 min. On days 7, 14, 21, 28, 60, and 90 after surgery, the grafted sites were examined by blinded observers to compare the healing and inflammation of the areas.

Results

All the 17 patients completed the surgeries and follow-up examinations. Direct examination revealed significantly better healing in EPO group only on the 28th day. Assessment of the photographs showed a significant value in favor of the test group at some other time points as well. The EPO group demonstrated less inflammation, which was statistically significant in many time points. The graft area was 80.88 ± 30.21 mm² and 71.35 ± 15.62 mm² in the EPO and control groups, respectively. The difference was not significant, though.

Conclusions

Topical application of erythropoietin can accelerate the healing of gingival grafts and reduce the inflammation during healing period. The final graft outcome, nevertheless, does not seem to be influenced by EPO.

Trial registration This was a split-mouth randomized controlled clinical trial (IRCT201201278830N1). The first registration date: 2016-10-22

Effect of microthread design on the preservation of marginal bone around immediately placed implants: a 5-years prospective cohort study

Background

This study aimed to evaluate the effect of the microthread design at the implant neck on the preservation of marginal bone around immediately-placed implants in a 5-year follow up.

Methods

Thirty patients received 41 immediately placed implants which were randomly assigned to treatment groups with microthreaded implants (test group, n = 22) or threaded implants (control group, n = 19). Clinical and radiographic analyses were carried out after 1 and5 years. Plaque index, bleeding on probing, suppuration, probing depth and marginal bone loss were subject to evaluations. The results were analyzed with the T-test, Fisher’s exact test and Mann–Whitney U test.

Results

No implants failed; thirty-five implants (in 27 patients); 21 microthreaded and 14 threaded implants; completed the 5 year follow up. The mean values of the marginal bone loss in microthreaded and threaded groups were 1.12 ± 0.95 mm and 0.87 ± 0.78 mm, respectively during an observation period of 70.9 ± 10.4 months; the differences in marginal bone loss and other pre-implant parameters were not significant between groups (P > 0.05).

Conclusion

Both implant designs showed acceptable results in terms of the clinical parameters and marginal bone level. Within the limitation of this study, the results did not demonstrate any superiority of the microthread design compared to threaded one in marginal bone preservation around immediately placed implants over 5 years of loading.

Characterization of a xenograft model for anti-CD19 CAR T cell studies

PURPOSE

Chimeric antigen receptor (CAR) T cell development for B cell malignancies treatment has triggered a paradigm shift in oncology. The development of anti-CD19 CAR T cells relies primarily on a panel of cell line-derived xenograft models, including Raji cells; however, the behavior of this model is under debate. We attempted to characterize this lymphoma model and propose outcome measures for CAR T cell studies METHODS: Raji cell line was inoculated into NOG mice via intra-venous (IV), intra-peritoneal (IP), and subcutaneous (SC) routes with different inoculum sizes, and consequent clinical and histopathological outcomes were assessed.

RESULTS

Inoculum sizes of 10⁵-10⁶ resulted in a complete take rate. The mice with IV and SC-inoculated Raji cells presented the shortest and longest survival among lymphoma-bearing mice, respectively (P < 0.01). The IP group had the highest number of both infiltrated organs (P < 0.05; compared to SC) and involvement of lymphatic sites (P < 0.05; compared to IV). The number of lymphoma lesions on the liver was higher in the IV compared to IP (P < 0.001) and SC (P < 0.05).

CONCLUSION

We demonstrate that the Raji cell line inoculation route could determine the xenograft model system behavior in terms of survival, tumor burden, and dissemination pattern and gives the model the specific features suitable for testing the specific hypothesis in CAR T cell therapy. We also conclude outcome measures for CAR T cell studies that do not require imaging techniques.

Linking plant and soil indices for water stress management in black gram

Measurement of plant and soil indices as well as their combinations are generally used for irrigation scheduling and water stress management of crops and horticulture. Rapid and accurate determination of irrigation time is one of the most important issues of sustainable water management in order to prevent plant water stress. The objectives of this study are to develop baselines and provide irrigation scheduling relationships during different stages of black gram growth, determine the critical limits of plant and soil indices, and also determine the relationships between plant physiology and soil indices. This study was conducted in a randomized complete block design at the four irrigation levels 50 (I₁), 75 (I₂), 100 (I₃ or non-stress treatment) and 125 (I₄) percent of crop's water requirement with three replications in Urmia region in Iran in order to irrigation scheduling of black gram using indices such as canopy temperature (T_c), crop water stress index (CWSI), relative water content (RWC), leaf water potential (LWP), soil water (SW) and penetration resistance (Q) of soil under one-row drip irrigation. The plant irrigation scheduling was performed by using the experimental crop water stress index (CWSI) method. The upper and lower baseline equations as well as CWSI were calculated for the three treatments of I₁, I₂ and I₃ during the plant growth period. Using the extracted baselines, the mean CWSI values for the three treatments of I₁, I₂ and I₃ were calculated to be 0.37, 0.23 and 0.15, respectively, during the growth season. Finally, using CWSI, the necessary equations were provided to determine the irrigation schedule for the four growing stages of black gram, i.e. floral induction-flowering, pod formation, seed and pod filling and physiological maturity, as (T_c - T_a)_c = 1.9498 - 0.1579(AVPD), (T_c - T_a)_c = 4.4395 - 0.1585(AVPD), (T_c - T_a)_c = 2.4676 - 0.0578(AVPD) and (T_c - T_a)_c = 5.7532 - 0.1462(AVPD), respectively. In this study, soil and crop indices, which were measured simultaneously at maximum stress time, were used as a complementary index to remove CWSI constraints. It should be noted that in Urmia, the critical difference between the canopy temperature and air temperature (T_c - T_a), soil penetration resistance (Q), soil water (SW) and relative water content (RWC) for the whole growth period of black gram were - 0.036 °C, 10.43 MPa and 0.14 cm³ cm^-3 and 0.76, respectively. Ideal point error (IPE) was also used to estimate RWC, (T_c - T_a) and LWP as well as to select the best regression model. According to the results, black gram would reduce its RWC less through reducing its transpiration and water management. Therefore, it can be used as a low-water-consuming crop. Furthermore, in light of available facilities, the farmer can use the regression equations between the obtained soil and plant indices and the critical boundaries for the irrigation scheduling of the field.

The influence of harvesting free gingival graft on self-reported pain perception: A randomized two-arm parallel clinical trial

Background/purpose

Free gingival graft (FGG) is used as an effective method to increase the width of keratinized tissue. However, it can cause pain at the donor site. Techniques accompanied by lesser tissue harvesting can reduce pain after surgery. The purpose of this study was to evaluate the self-reported pain perception following harvesting FGG using conventional and accordion methods.

Materials and methods

In this randomized clinical trial study, 31 patients with a deficiency of keratinized tissue around implant were investigated. Sixteen subjects in the accordion group and 15 subjects in the control group received conventional FGG. In the accordion group, FGG was harvested with a length of 60% of the mesiodistal length of the recipient area and with the same length as the mesiodistal length of the recipient area in the conventional group. The patients were asked to record their daily pain using a numerical rating scale.

Results

The severity of the pain after reaching to the peak on the second day was reduced and reached zero at day 14 in both groups. Pain severity showed no significant difference between the treatment groups. The highest level of pain was reported in the conventional group in those subjects under 50 years old, and the lowest one was in the conventional group's subjects above 50 years old. There was no difference between men and women in the reported pain between the treatment groups.

Conclusion

Harvesting graft with a smaller size in the accordion group has no effect on reducing pain.

Registration number

IRCT20190721044296N1.

Attenuation correction for myocardial perfusion imaging

Aim: We investigated the impact of photon attenuation in myocardial perfusion imaging with SPECT and PET in patients with coronary artery disease. In fact, the regional tracer distribution can be quantitatively assessed by polar map analysis if the effects of photon attenuation are accounted for. PET imaging permits accurate measurement of and correction for photon attenuation, whereas results of attenuation correction in SPECT imaging have been inconsistent. Patients, methods: We compared photon attenuation in resting perfusion imaging studies with SPECT (99mTc-sestamibi) and PET (13N-ammonia) from 21 patients. Transaxial images were reconstructed with and without attenuation correction and reoriented into short axis images. Polar map analysis was utilized to generate regional tracer uptake in six anatomical segments. Results: Average segmental photon attenuation calculated as the ratio of counts in corrected and uncorrected images was 7.2 ± 1.4 in SPECT and 14.0 ± 3.1 in PET imaging (p <0.01). This attenuation factor was significantly related to body mass index for both methods (p <0.001). While attenuation correction for SPECT imaging did compensate for attenuation effects in the inferior wall (from –15% to +6% vs. PET), relative tracer uptake in the anterior wall in SPECT images was significantly reduced after attenuation correction (from –2% to –18% vs. PET, p <0.01). Conclusion: Differential effects of attenuation correction for myocardial SPECT perfusion imaging need to be considered when algorithms designed to compensate effects of photon attenuation in SPECT imaging are employed in clinical practice.

Radiographic Comparison of Bovine Bone Substitute Alone Versus Bovine Bone Substitute and Simvastatin for Human Maxillary Sinus Augmentation

Objectives:

The aim of this study was to compare the efficacy of bovine bone substitute (Compact Bone B. ®) alone versus bovine bone substitute and simvastatin for human maxillary sinus augmentation.

Materials and Methods:

This study was conducted on 16 sinuses in eight patients. Radiographic assessments were done preoperatively (T0), immediately (T1) and at nine months after sinus grafting (T2). Alveolar bone height and density were assessed on cone beam computed tomography (CBCT) scans using Planmeca Romexis™ Imaging Software 2.2.

Results:

The change in alveolar bone height and density between T0, T1 and T2 was significant in both groups. Alveolar bone height (h0, h1, h2) and vertical height of the grafted bone (g1, g2) in three lines (anterior, middle and posterior) were not significantly different between groups. The grafted bone height shrinkage (%) in the anterior, middle and posterior limits of the augmented area were not significantly different between groups. The existing alveolar and grafted bone density increased significantly in both groups between T1 and T2, except for the existing alveolar bone density in the control group. There were no statistically significant differences between the alveolar bone density values obtained in TI and T2 between groups, except for the existing alveolar bone density at T1.

Conclusions:

This study did not show any significant positive effect for simvastatin in maxillary sinus augmentation based on radiographic examination.

Modified Pedicle Grafting: A Novel Noninvasive Technique for Soft Tissue Augmentation Around Maxillary Dental Implants

OBJECTIVES

This study sought to assess the efficacy of modified pedicle grafting as a noninvasive technique for soft tissue augmentation around maxillary dental implants.

MATERIALS AND METHODS

This descriptive study was conducted on eight patients who met the inclusion criteria. Prior to the second-stage surgery for exposing the implants, the buccal keratinized mucosa width, vestibular depth, and mucosal thickness around the implants were measured. The same parameters were measured six months after the second-stage surgery and were compared with the baseline values. Also, the color match of the graft with the adjacent gingival and mucosal tissues was evaluated.

RESULTS

Forty-seven maxillary implants were evaluated. The minimum and maximum gains of keratinized mucosal width were respectively equal to 0mm and 7mm, with a mean of 4.31±1.19mm. The mean vestibular depth around the implants was 9.47±1.75mm (ranging from 5mm to 12mm) six months after the surgery. At the beginning of the study, a thin mucosa surrounded the implants, but after six months, the peri-implant keratinized mucosa width increased. The color match of the graft with the adjacent gingival and mucosal tissues was excellent based on the periodontists' opinion.

CONCLUSIONS

Modified pedicle grafting is a safe and predictable technique for soft tissue augmentation around maxillary implants. This technique is reliable for increasing the width of keratinized mucosa in fully and partially edentulous patients with a shallow vestibular depth. The stability of the pedicle flap is achieved by fixing the flap to the tissue around the healing abutment.

Periosteal Releasing Incision With Diode Laser in Guided Bone Regeneration Procedure: A Case Series

Introduction: Periosteal releasing incision (PRI) is nearly always essential to advance the flap sufficiently for a tension-free flap closure in bone augmentation procedures. However, hematoma, swelling, and pain are recognized as the main consequences of PRI with scalpel. The aim of this case series was to investigate the effectiveness of laser-assisted PRI in guided bone regeneration (GBR) procedure. In addition, postoperative hematoma, swelling, and pain and implant success were assessed. Methods: Seventeen patients needed GBR were included in this study. Diode laser (940 nm, 2 W, pulse interval: 1 ms, pulse length: 1 ms, contact mode, 400-μm fiber tip) was used in a contact mode to cut the periosteum to create a tension-free flap. Facial hematoma, swelling, pain, and the number of consumed nonsteroidal anti-inflammatory drugs (NSAIDs) were measured for the six postoperative days. Six months after implant loading, implant success was evaluated. Results: Minimal bleeding was encountered during the procedure. A tension-free primary closure of the flap was achieved in all cases. The clinical healing of the surgical area was uneventful. None of the patients experienced hematoma, ecchymosis, or intense swelling after surgery. The mean value of maximum pain (visual analogue scale - VAS) was 20.59 ± 12.10 mm (mild pain). Patients did not need to use NSAID after four postoperative days. All implants were successful and functional and none of them failed after 6 months of implant loading. Conclusion: This study revealed the effectiveness of laser-assisted PRI in GBR procedure. This technique was accompanied with minimal sequelae at the first postoperative week. All implants were successful and no complication was noted during the course of this study.

Role of Anatomic and Salivary Factors in Dental Calculus Formation in Primary and Mixed Dentition Stages

PURPOSE

Clinical experience shows that formation of calculus is a very rare phenomenon in primary teeth, but it increases as the permanent teeth erupt. The purpose of this study was to assess the relationship between dental calculus, dental anatomy, and salivary factors in primary and mixed dentition stages.

METHODS

A cross-sectional study was carried out to determine the buccolingual dimensions of the most concave and the most convex surfaces of the lingual aspect of mandibular central incisor crowns in a sample group of 120 three- to five-old children and 120 eight- to 10-year old children. Saliva samples were collected from 20 in each group. Data were analyzed using t tests.

RESULTS

Significant differences were found between the ratio of the buccolingual dimensions of the most convex to the most concave areas of the lingual surfaces in primary and permanent incisors (P=0.028). Saliva analysis revealed significant differences in total protein (P=0.002), sodium (P=0.037), bicarbonate (P=0.003), and ammonia (P=0.025) between the two age groups.

CONCLUSIONS

Anatomic and salivary factors may be important reasons for the differences in calculus formation.

Oral health status, knowledge, attitude and practice of patients with heart disease

BACKGROUND

The aim of this study was to investigate knowledge, attitude and practice (KAP) of cardiovascular disease (CVD) patients about their oral health status.

METHODS

In this cross-sectional study, we analyzed the data of 150 CVD patients that collected by a self-administered questionnaire consists of demographic characteristics and KAP. Oral health indicators calculated based on the results of oral examination by an expert dentist.

RESULTS

CVD patients had an overall moderate level of knowledge and attitude, but their practice was lower than moderate. There were important associations between knowledge scores with gender, education, residential area and financial status, between attitude scores with education and residential area, and between practice scores with education and financial status. There were no associations between KAP and age, marital status or job. Significant positive correlations were found between KAP components. Significant negative correlations were found between oral hygiene index with knowledge and practice.

CONCLUSION

The practice of heart disease patients about their oral health was poor, and declares that increasing awareness and attitude may not promote practice. Efficient programs are needed to promote oral health practice of adult populations in special groups.

Evaluation of Salivary Leptin Levels in Healthy Subjects and Patients with Advanced Periodontitis

OBJECTIVES

Leptin is a hormone-like protein produced by the adipose tissue. It plays an important role in protection of host against inflammation and infection. Some studies have reported changes in leptin levels in the gingival crevicular fluid (GCF), saliva and blood serum of patients with periodontal disease compared to healthy individuals. The aim of the present study was to compare the salivary leptin levels in patients with advanced periodontitis and healthy individuals.

MATERIALS AND METHODS

In this case-control study, the salivary samples of healthy individuals and patients with advanced periodontitis with clinical attachment loss >5mm were obtained using a standardized method and the leptin levels were measured in the salivary samples by means of ELISA. The effects of the periodontal status and sex on the salivary leptin levels of both groups were statistically analyzed by two-way ANOVA.

RESULTS

The means ± standard deviation (SD) of salivary leptin levels in healthy subjects and patients with advanced periodontitis were 34.27±6.88 and 17.87±5.89 pg/mL, respectively. Statistical analysis showed that the effect of sex on the salivary leptin levels was not significant (P=0.91), while the effect of advanced periodontitis on the salivary leptin levels was significant compared to healthy individuals (P<0.0001).

CONCLUSIONS

In patients with advanced periodontitis, the salivary leptin levels were significantly lower compared to healthy individuals. Thus, assessment of salivary leptin can be done as a non-invasive and simple method to determine the susceptibility of patients to advanced periodontitis.

Frequency of Dental Implants Placed in the Esthetic Zone in Dental Clinic of Tehran University: A Descriptive Study

OBJECTIVES

Anterior maxilla, known as the esthetic zone, plays an important role in facial and smile esthetics. This study assessed the frequency of implant treatments in the esthetic zone of patients presenting to Dental Implant Department of Tehran University during 2002-2012.

MATERIALS AND METHODS

This descriptive study was conducted on dental records of patients receiving implant treatment during 2002-2012. Patient records were retrieved from the archives and patient demographics, implant characteristics, failure rate, prevalence of complications and implant systems were collected. The data were reported as frequency and percentage.

RESULTS

Of a total of 2,381 implants placed in the mentioned time period, 492 (20.8%) had been placed in the anterior maxilla and 531 (22.3%) had been placed in the anterior mandible from canine to canine. Timing of implant placement was immediate in 12.0%, early in 0.5% and late in 87.4%. Survival rate was 99.1%. Rate of failure was 0.8%. Failure rate was 0.4% in the maxillary and 1.1% in the mandibular canine to canine region. Complications were reported in 10.1% of patients. Rate of complications was 18.3% in the maxillary canine to canine, 8.9% in the mandibular canine to canine, 18.1% in the maxillary first premolar to first premolar and 9.5% in the mandibular first premolar to first premolar. The frequency of bone grafts placed in these areas was 17.6%, 33.9%, 13.6%, 32.1% and 14.3%, respectively.

CONCLUSION

Of implants placed in our center, around 20% were in the anterior maxilla, and delayed implant placement was the most commonly adopted technique.

Cementogenesis in Patients with Localized Aggressive Periodontitis

OBJECTIVES

The aim of this study was to determine the cementum thickness in the first molars of patients with localized aggressive periodontitis (LAP) compared to healthy individuals.

MATERIALS AND METHODS

This case-control study compared eight first molar teeth affected by LAP with eight third molar teeth of healthy individuals. The teeth were disinfected by immersion in 10% buffered formalin solution for three days and were then sectioned. External mesial root surfaces (middle one-third) were evaluated under a stereomicroscope by a blinded pathologist to determine the mean thickness of cementum. SPSS software (version 16.0) and t-test were used for statistical analysis.

RESULTS

Histological examination revealed a significant difference between the two groups in terms of the amount of cementogenesis (P<0.001) .The thickness of cementum was higher in the control group (105.16±11.5 μm) than in LAP patients (86.44±7.3 μm).

CONCLUSION

This study demonstrated the presence of cementum hypoplasia in mesial root surfaces of first molars affected by LAP.

Importance of customer adjustment regions in the non-clinical property of thought: A home examination in low and high-income areas of Mashhad

Responsiveness was proposed via WHO as a fundamental sign to evaluate the enforcement of wellness practices and evaluates with a standard organization of fields that are classified to 2 principal classes "Respect as characters" and "customer adjustment". The current research included the value of customer adjustment areas in low and high-income communities of Mashhad. In the current descriptive research, an example of 923 families was chosen stochastically of 2 low and high pay areas of Mashhad. WHO survey employed for information gathering. Regular rate reviews and Ordinal Logistic Regression (OLR) applied for information investigation. In overall, respondents chose basic amenities quality as the primary area, and the path to social care networks recognized as the wicked primary area. Families in high-income states obtained higher areas of immediate notations and selection associated with low-income. There is a meaningful correlation among parameters of ages, having a part whom required care and self-imposed health via the ranking of customer adjustment areas. The investigation of the homes' viewpoint concerning the classification of non-clinical perspectives of care quality, particularly while confronted by restricted sources, can assist in managing enterprises towards topics that are more relevant and results in the development of the wellness policy achievement and fecundity.

Evaluation of Platform Switching on Crestal Bone Stress in Tapered and Cylindrical Implants: A Finite Element Analysis

PURPOSE

To analyze and compare the stress distribution around tapered and cylindrical implants and investigate how different abutment diameters influence crestal bone stress levels.

MATERIALS AND METHODS

Six finite element models of an abutment (5 mm, 4.3 mm, and 3.5 mm in diameter) and supporting implants (tapered and cylindrical) were designed. A vertical force of 100 N and a 15-degree oblique force of 100 N were applied separately on the occlusal surface, and von Misses stresses were evaluated in the cortical and cancellous bone.

RESULTS

Higher stress was observed under oblique loading than under vertical loading of both tapered and cylindrical implants. Tapered implants demonstrated more stress under both vertical and oblique loading. Platform switching reduced peri-implant crestal bone stress in all models under vertical and oblique forces. The peri-implant crestal bone around tapered implants experienced 4.8% more stress under vertical loading and 35% more stress under oblique loading in comparison to bone around cylindrical implants (2.62 MPa with vertical loading, 8.11 MPa under oblique loading). Oblique loads resulted in much higher stress concentrations in the peri-implant crestal bone than vertical loads (238% in cylindrical and 308% in tapered implants). When the abutment diameter decreased, both models showed reductions of stress in the crestal bone under both types of loading.

CONCLUSION

In this finite element analysis, tapered implants increased crestal bone stress upon loading, and platform switching minimized the stress transmitted to the crestal bone in both tapered and parallel wall implants.

Assessment of interleukin-1beta and interleukin-6 in the crevicular fluid around healthy implants, implants with peri-implantitis, and healthy teeth: a cross-sectional study

Objectives

This study aimed to assess and compare the levels of interleukin-1beta (IL-1β) and interleukin-6 (IL-6) in the crevicular fluid around healthy implants, implants with peri-implantitis, and healthy teeth.

Materials and Methods

This study evaluated 16 dental implants in 8 patients (4 males and 4 females). These patients had at least one healthy implant and one implant with peri-implantitis next to healthy teeth. The crevicular fluid was collected using absorbent cones and transferred to the laboratory. Specimens were evaluated by ELISA for interleukin levels. Data were analyzed using repeated measures ANOVA and Bonferroni tests (P<0.05).

Results

Levels of IL-1β in the crevicular fluid around implants with peri-implantitis were significantly higher than around healthy implants (P=0.002); the latter was significantly higher than around healthy teeth (P=0.015). A significant difference was found in the level of IL-6 in the crevicular fluid around implants with peri-implantitis and healthy implants (P=0.049) and also between implants with peri-implantitis and healthy teeth (P<0.001).

Conclusion

Within the limitations of this study, significant differences exist in the levels of IL-1β and IL-6 in the crevicular fluid of implants with peri-implantitis, healthy implants, and healthy teeth. More studies with larger sample sizes in different populations are necessary.

Comparison of the penetration and passage of Streptococcus mutans and Aggregatibacter actinomycetemcomitans through membranes loaded with tetracycline, amoxicillin, and chlorhexidine: an in vitro study

BACKGROUND

This study aimed at comparing the colonization and passage of Streptococcus mutans and Aggregatibacter actinomycetemcomitans (Aa) through polytetrafluoroethylene (PTFE) and acellular dermal matrix (ADM) membranes loaded with tetracycline, amoxicillin, and chlorhexidine.

METHODS

In this in vitro study, PTFE and ADM membranes were loaded with tetracycline, amoxicillin, and chlorhexidine. The colonization and crossing of S. mutans and Aa through these membranes were evaluated using vials containing culture medium. Three-way analysis of variance and Tukey's honestly significant difference test were used for the statistical analyses (p<0.05).

RESULTS

The membranes loaded with antimicrobial agents significantly decreased bacterial passage compared with the control membranes (not loaded with antimicrobial agents). Significant differences were also detected between membranes in their inhibitory properties (p=0.011). PTFE membrane had higher barrier effect than ADM. Tetracycline had greater antibacterial activity against both species compared with amoxicillin (p=0.021) but had no significant difference with chlorhexidine in this respect (p=0.068). The antimicrobial efficacy of chlorhexidine was in between those of tetracycline and amoxicillin, but the difference between amoxicillin and chlorhexidine in this respect was not statistically significant (p=0.992). Aa had better penetration into the membranes compared with S. mutans.

CONCLUSIONS

The study results demonstrated that the penetration of S. mutans and Aa decreased into the membranes loaded with tetracycline, amoxicillin, and chlorhexidine and PTFE membrane had a greater barrier effect than ADM. Loading membranes with antimicrobial agents can effectively reduce membrane-associated infections during regenerative procedures.

Isolation and Assessment of Mesenchymal Stem Cells Derived From Bone Marrow: Histologic and Histomorphometric Study in a Canine Periodontal Defect

The aim of the present study was to investigate an isolation procedure to culture mesenchymal stem cells derived from bone marrow and evaluate their potential in periodontal regeneration. Potential stem cells from bone marrow, aspirated from the iliac crest of nine mongrel canines 1 to 2 years of age, were cultivated. After the examination of surface epitopes of the isolated cells, the total RNA from osteogenic, adipogenic, and chondrogenic cell cultures were analyzed by reverse transcription polymerase chain reaction (RT-PCR) to confirm stem cell gene expressions. 2 × 10(7) mL of the stem cells were loaded on 0.2 mL of anorganic bovine bone mineral (ABBM) granules. In each animal, bilateral acute/chronic intrabony periodontal defects were created surgically and by placement of ligatures around the cervical aspect of the teeth. At week 5, after flap debridement, the bilateral defects were randomly assigned to 2 treatment groups: the control group received ABBM, and the test group received BMSCs-loaded ABBM. Eight weeks after transplantation, regenerative parameters were analyzed histologically and histometrically. The RNA expressions confirmed the cultivation of mesenchymal stem cell. More new cementum and periodontal ligament (PDL) were measured in the test group (cementum: 3.33 ± 0.94 vs 2.03 ± 1.30, P = 0.027; PDL: 2.69 ± 0.73 vs 1.53 ± 1.21, P = 0.026). New bone formation was similar in both groups (2.70 ± 0.86 vs 1.99 ± 1.31; P = 0.193). Mesenchymal stem cells derived from bone marrow should be considered a promising technique for use in patients with periodontal attachment loss and merits further investigations.

Is biologic width of anterior and posterior teeth similar?

The biologic width (BW) includes attached epithelial cells and connective tissue attachment complex being very important in the periodontal health during prosthetic treatments as invading this zone can cause bone resorption and gingival recession. The present study investigated biologic width values in the normal periodontium in anterior and posterior teeth. 30 patients that referred from restorative department to periodontics department of Tehran University of medical sciences who need crown lengthening procedure on their teeth with no history of orthodontic, prosthodontic and periodontal treatment were randomly enrolled in this cross-sectional trial. Sulcus depths (SD) as well as the distance between free gingival margin and the bone crest (FB) of anterior and posterior teeth were measured by UNC-15 probe and compared. periodontium thickness was also assessed. The data were subjected to Student t test. Mean BW in the 43 anterior and 47 posterior teeth was measured and not significantly different (1.4651±0.39 mm vs. 1.6312±0.49 mm) was observed; however, BW was significantly more in the teeth with thick periodontium compared to those with thin periodontium (1.703±0.5 vs. 1.408±0.35; P=0.002). BW not only is different in individuals but also could be dissimilar in different teeth and should be calculated independently prior to restorative treatments.

Periodontal parameters following orthodontic treatment in patients with aggressive periodontitis: A before-after clinical study

BACKGROUND

The success of combined periodontal and orthodontic approach in the treatment of aggressive periodontitis patients with the pathologic extruded anterior teeth is a main concern and stability of the treatment results is an important factor to evaluate the treatment. The present study investigated the periodontal parameters at the end of the orthodontic treatment in patients with the aggressive periodontitis.

MATERIALS AND METHODS

Eight patients with an aggressive periodontal disease, extruded maxillary incisors, infrabony defects and probing depth of ≥5 mm were enrolled in this clinical trial (before, after). After periodontal therapy, orthodontic treatment was carried out for intrusion and alignment of teeth. Plaque index (PI), probing pocket depth (PPD), distance between incisal edge and interdental papilla, root length (RL), and defect dimensions (depth and width) were examined at the end of treatment and three as well as 6 months afterward. The data were subjected to repeated measure ANOVA test. P < 0.05 was considered as significant.

RESULTS

There was statistically significant decrease in PPD, PI, and depth of the defects during T0, T3 and T6 (P < 0.05). No significant differences were observed in the RL and distance between incisal edge and interdental papilla (P = 0.95). Furthermore, width of the defects demonstrated significant decrease up to T3 (P = 0.042) while no significant changes from 3 months to 6 months were noted (P = 0.59).

CONCLUSION

The results showed that combined periodontal and orthodontic approach would be a successful treatment with acceptable stability in the case of regular follow-up visits and controlled oral hygiene habits.

Designing and standardizing a questionnaire for evaluating knowledge, attitude, and practice of Iranian adults with cardiovascular diseases about oral health

BACKGROUND

Cardiovascular diseases are the most common cause of death in Iran. Moreover, periodontal diseases are very common in our country. In this study, we have designed a standardized questionnaire for evaluating knowledge, attitude, and practice (KAP) of Iranian adult patients with cardiovascular diseases about oral health.

METHODS

For designing and standardizing a self-administered questionnaire, we performed a cross-sectional pilot study on 51 cases with periodontal complaints. A dentist carried out the physical examination to determine oral health indicators. Twelve experts and ten lay people of the target population answered questions about validity. Cronbach's alpha, factor analysis, and Pearson correlation coefficients were used in the analysis.

RESULTS

The cases of this pilot study were middle aged, with moderate financial and health status, but low oral health and educational level. Debris score was correlated with all other physical exam findings except decay, missing, and filled (DMF). Reliability was 0.826 according to Cronbach's alpha score. Face validity was higher than 80%. Content validities of the whole of the questionnaire were 85.98% for clarity, 78.05% for relevancy, 85.16% for simplicity, and 82.32% for consistency of each question with the question set. Factor analysis showed that 15 components explain 74% of the total variance.

CONCLUSION

This questionnaire is culturally adjusted and appropriate for our community, valid and reliable, and sufficiently estimates the variance of the oral health status. It can be used as a standard tool in further studies in adult population of the Iranian middle aged patients with low level of education and moderate socioeconomic status.

Comparison of amnion allograft with connective tissue graft for root coverage procedures: a double-blind, randomized, controlled clinical trial

OBJECTIVE

The aim of the present double-blind, randomized, controlled study was to evaluate and compare the efficacy of amnion allograft and connective tissue graft in covering denuded root surfaces.

METHODS

Seventy-one teeth in 22 patients with gingival recession were treated randomly with coronally displaced flap plus connective tissue graft (control group, n = 29 recessions in 10 patients) or coronally displaced flap plus amnion allograft (test group, n = 42 recessions in 12 patients). The amount of root coverage and clinical parameters (probing depth, recession depth, clinical attachment level, recession width, gingival width, and papilla dimensions) were measured at baseline and at 3 and 6 months postoperatively.

RESULTS

Average root coverage percentages after 6 months in the test and control groups were 67% (2.3 +/- 0.289 mm) and 54% (2.24 +/- 0.519 mm), respectively, with no statistically significant differences (p = 0.054). The changes in depth and width of recessions and in gingival width were significant 3 and 6 months after surgery compared to baseline (p = 0.000). Variations in the level of attachment and probing depths after 6 months were statistically significant in the test group compared to the control group (p = 0.002). Papilla dimensions were significantly correlated with root coverage (p = 0.00).

CONCLUSIONS

Amnion allograft might be a suitable alternative to connective tissue graft in procedures to cover denuded root surfaces and can reduce recession depth.

Autologous dental pulp stem cells in regeneration of defect created in canine periodontal tissue

This study aimed to investigate effects of dental pulp stem cells (DPSCs) on regeneration of a defect experimentally created in the periodontium of a canine model. Surgically created mesial 3-walled periodontal defects with ligature-induced periodontitis were produced bilaterally in the first lower premolar teeth of 10 mongrel dogs. Simultaneously, DPSCs were derived from the maxillary premolar teeth of the same dogs. Four weeks after creation of the periodontitis model, autologous passaged-3 DPSCs combined with Bio-Oss were implanted on one side as the test group. On the other side, only Bio-Oss was implanted as a control. Eight weeks after surgery, regeneration of the periodontal defects was evaluated histologically and histomorphometrically in terms of bone, periodontal ligament (PDL), and cement formation. Histologically, in all test specimens (10 defects), regeneration of cementum, bone, and PDL was observed. In the control groups, although we observed the regeneration of bone in all defects, the formation of cementum was seen in 9 defects and PDL was seen in 8 defects. Histomorphometric analyses showed that the amount of regenerated cementum and PDL in the test groups (3.83 ± 1.32 mm and 3.30 ± 1.12 mm, respectively) was significantly higher than that of the control groups (2.42 ± 1.40 mm and 1.77 ± 1.27 mm, respectively; P < .05). A biocomplex consisting of DPSCs and Bio-Oss would be promising in regeneration of periodontal tissues.

Comparison of interleukin-1β levels in gingival crevicular fluid and peri-implant crevicular fluid and its relationship with clinical indexes

OBJECTIVE

Interleukin-1β (IL-1β) is one of the most important cytokines which seems to have an important role in the inflammatory process in gingival and peri-implant tissues. The aim of this split-mouth study was to investigate the relationship between the concentration of IL-1β in gingival crevicular fluid (GCF) and peri-implant crevicular fluid (PICF) and clinical parameters such as plaque index (PI), gingival index (GI), pocket depth (PD) and bone loss (BL).

MATERIALS AND METHODS

In 32 patients, PICF and GCF samples of 41 implants and 41 contralateral teeth were collected and IL-1β was determined by enzyme-linked immunosorbent assay (ELISA). PI,GI,PD and BL were recorded for each of the samples.

RESULT

The positive correlation between the level of IL-1β and PI, GI, PD and BL in both groups was observed (P<0.0001). In similar conditions, the level of IL-1β was greatly higher in PICF than GCF (75.26 pg/μl and 45.71 pg/μl, respectively) (P=0.001).

CONCLUSION

The findings of the present study indicated that the level of IL-1β may be an important supplement to clinical findings in measuring the health status of gingival or peri-implant tissues.

Histological evaluation of Accell Connexus(®) and Bio-Oss(®) on quality and rate of bone healing: a single blind experimental study on rabbit's calvarium

OBJECTIVE

The objective of this study was to evaluate the effect of Accell Connexus(®) on the quality and rate of healing in experimental defects of rabbit calvarium compared to Bio-Oss®.

MATERIALS AND METHODS

Twelve 2.5-3.5 kg weighing New Zealand white rabbits were used. Three defects (3×6 mm) were created in the cranium of the animals subsequently filled with Accell Connexus(®), Bio-Oss® or served as controls. The animals were sacrificed four, six and eight weeks postoperatively and the histology blocks were studied in terms of inflammation, trabeculation thickness, bone type regeneration, foreign body and remained biomaterial by light microscope. The data were subject to Mann-Whitney U test.

RESULTS

Increased inflammatory reaction, foreign body reaction, delayed bone formation and lower rate of ossification were observed in DBM-filled defects compared to Bio-Oss® or controls. However, no significant differences were observed in bone formation between Bio-Oss®, Accell Connexus(®) and control specimens in the three time intervals. Furthermore, no significant differences were noted between Bio-Oss® and control groups.

CONCLUSION

Accell Connexus(®) showeda lower rate of ossification and bone healing compared to Bio-Oss® or controlgroups. Other studies in this field seem necessary.

Assessment of left ventricular volumes, ejection fraction and mass

Aim: We compared and delineated possible differences of model-based analysis of ECGgated SPECT using 99mTc-sestamibi (Tc- SPECT) with ECG-gated 18F-fluorodeoxyglucose- PET (FDG-PET) for determination of enddiastolic (EDV) and end-systolic (ESV) cardiac volumes, left ventricular ejection fraction (LVEF), and myocardial mass (LVMM). Patients, methods: 24 patients (21 men; age: 54 ± 12years) with coronary artery disease underwent Tc-SPECT and FDG-PET imaging for evaluation of myocardial perfusion and viability. By using model-based analysis EDV, ESV, LVEF and LVMM were calculated from short axis images of both Tc-SPECT and FDGPET. Results: Left ventricular volumes by Tc- SPECT and FDG-PET were 176 ± 60 ml and 181 ± 59 ml for EDV, and 97 ± 44 ml and 103 ± 45 ml for ESV respectively, LVEF was 47 ± 8% by Tc-SPECT and 45 ± 9% by FDG-PET. The LVMM was 214 ± 40 g (Tc-SPECT) and 202 ± 43 g (FDG-PET) (all p = NS, paired t-test). A significant correlation was observed between Tc-SPECT and FDG-PET imaging for calculation of EDV (r = 0.93), ESV (r = 0.93), LVEF (r = 0.83) and LVMM (r = 0.72). Conclusion: ECG-gated Tc-SPECT and FDG-PET using two tracers with different characteristics (perfusion versus metabolism) showed close agreement concerning measurements of left ventricular volumes, contractile function and myocardial mass by using a model-based analysis.

Radiographic Vertical Bone Loss Evaluation around Dental Implants Following One Year of Functional Loading

OBJECTIVE

Vertical bone loss evaluations in the Nobel Biocare Replace(®) Select Tapered (™) implant system in the human after one-year loading time.

MATERIALS AND METHODS

This retrospective cross-sectional study was performed on 31 patients (14 men, 17 women; mean age, 60.39 years) receiving 170 implants (mean, 5.48 for each patient) of Groovy and Non-groovy designs in the Nobel Biocare Replace(®) Select Tapered (™) system. The marginal bone loss was measured at mesial and distal aspects of the implants on OPG x-rays after one-year follow-up. The data regarding the patient's gender, age, history of disease, smoking, bone type at implant location, loading time of prosthesis and implant, implant design, diameter and length were recorded by the patients' records and interview. The data were subjected to multiple linear regression and Pearson coefficient ratio regarding different factors.

RESULTS

The mean (standard deviation) distal, mesial and overall bone loss was 0.688 mm (0.851), 0.665 mm (0.849) and 0.935 mm (0.905), respectively in the studied implants. No significant differences were found regarding implant location, bone quality at the implant region, implant design and bone graft reception. In addition, no significant correlation was found between the occurred bone loss and implant diameter, length and number of used splints.

CONCLUSION

Due to the criteria mentioned for implant success in term of bone loss values after one-year loading time, Noble Biocare Replace(®) Select Tapered (™) implant system is an acceptable treatment option for implant restorations in this regard.

Myocardial blood flow in patients with low-flow, low-gradient aortic stenosis: differences between true and pseudo-severe aortic stenosis. Results from the multicentre TOPAS (Truly or Pseudo-Severe Aortic Stenosis) study

BACKGROUND

Impairment of myocardial flow reserve (MFR) in aortic stenosis (AS) with normal left ventricular function relates to the haemodynamic severity.

OBJECTIVES

To investigate whether myocardial blood flow (MBF) and MFR differ in low-flow, low-gradient AS depending on whether there is underlying true-severe AS (TSAS) or pseudo-severe AS (PSAS).

METHODS

In 36 patients with low-flow, low-gradient AS, dynamic [13N]ammonia PET perfusion imaging was performed at rest (n = 36) and during dipyridamole stress (n = 20) to quantify MBF and MFR. Dobutamine echocardiography was used to classify patients as TSAS (n = 18) or PSAS (n = 18) based on the indexed projected effective orifice area (EOA) at a normal flow rate of 250 ml/s (EOAI(proj )<or= or >0.55 cm(2)/m(2)).

RESULTS

Compared with healthy controls (n = 14), patients with low-flow, low-gradient AS had higher resting mean (SD) MBF (0.83 (0.21) vs 0.69 (0.09) ml/min/g, p = 0.001), reduced hyperaemic MBF (1.16 (0.31) vs 2.71 (0.50) ml/min/g, p<0.001) and impaired MFR (1.44 (0.44) vs 4.00 (0.91), p<0.001). Resting MBF and MFR correlated with indices of AS severity in low-flow, low-gradient AS with the strongest relationship observed for EOAI(proj) (r(s) = -0.50, p = 0.002 and r(s) = 0.61, p = 0.004, respectively). Compared with PSAS, TSAS had a trend to a higher resting MBF (0.90 (0.19) vs 0.77 (0.21) ml/min/g, p = 0.06), similar hyperaemic MBF (1.16 (0.31) vs 1.17 (0.32) ml/min/g, p = NS), but a significantly smaller MFR (1.19 (0.26) vs 1.76 (0.41), p = 0.003). An MFR <1.8 had an accuracy of 85% for distinguishing TSAS from PSAS.

CONCLUSIONS

Low-flow, low-gradient AS is characterised by higher resting MBF and reduced MFR that relates to the AS severity. The degree of MFR impairment differs between TSAS and PSAS and may be of value for distinguishing these entities.

Myocardial perfusion in patients with typical chest pain and normal angiogram

BACKGROUND

Approximately 10-30% of patients with typical chest pain present normal epicardial coronaries. In a proportion of these patients, angina is attributed to microvascular dysfunction. Previous studies investigating whether angina is the result of abnormal resting or stress perfusion are controversial but limited by varying inclusion criteria. Therefore, we investigated whether microvascular dysfunction in these patients is associated with perfusion abnormalities at rest or at stress.

PATIENTS AND METHODS

In 58 patients (39 female, 19 male, mean age 58+/-10 years) with angina and normal angiogram as well as 10 control patients with atypical chest pain and normal coronaries (six female, four male, mean age 53+/-11 years) myocardial blood flow (MBF) was measured at rest and under dipyridamole using 13N-ammonia PET. Resting MBF and coronary flow reserve (CFR) as the ratio of hyperaemic to resting MBF were corrected for rate-pressure-product (RPP): normalized resting MBF (MBFn)=MBFx10,000/RPP and CFRn=CFRxRPP/10,000.

RESULTS

Sixteen/58 patients had a normal CFRn (=2.5; group I; CFRn: 3.1+/-0.88); the same as the controls (CFRn: 3.3+/-0.74). Forty-two/58 patients presented a reduced CFRn (group II; CFRn: 1.78+/-0.57). Group II had both a higher MBFn (group II: 1.30+/-0.33 vs. Group I: 1.03+/-0.26; P<0.05 and vs. controls: 1.07+/-0.19; P<0.01) and a lower hyperaemic MBF (group II: 2.25+/-0.76 mL g-1 min-1 vs. Group I: 3.07+/-0.78 mL g-1 min-1; P<0.001 and vs. controls: 3.41+/-0.94 mL g-1 min-1; P<0.0001).

CONCLUSION

Impaired CFRn in patients with typical angina and normal angiogram is owing to both an increased resting and reduced hyperaemic MBF. Therefore, PET represents a prerequisite for further studies to optimize treatment in individuals with anginal pain and normal coronary angiogram.

FDG gamma camera PET equipped with one inch crystal and XCT. Assessment of myocardial viability

Metabolic imaging with 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) is actually considered as the best method to detect and quantitatively assess myocardial tissue viability. The aim of this study was to investigate the accuracy of FDG gamma camera positron emission tomography (GCPET) imaging equipped with one inch NaI crystals in comparison to FDG dedicated PET (dPET) imaging as a "gold standard" in phantom and clinical studies.

PATIENTS, METHODS

Nineteen patients with coronary artery disease (CAD) underwent both imaging modalities. Phantom and clinical GCPET imaging were performed with a dual-headed, coincidence based gamma camera equipped with 1 inch thick NaI crystals and an x-ray tube (XCT) for attenuation correction (AC), as well as with a dedicated PET scanner with AC. (99m)Tc tetrofosmin single-photon emission tomography (SPET) studies were performed for assessment of myocardial perfusion, with AC.

RESULTS

Phantom studies showed a significant relation in segmental activity between FDG imaging with AC using GCPET and dPET (r = 0.91, p < 0.001). In clinical studies with AC correlation coefficients of mean segmental FDG uptake and regional defect size were r = 0.87 (p < 0.0001) and r = 0.83 (p < 0.0001), respectively. In regional analysis close agreement was even found in the most attenuated regions of the heart if AC was used in GCPET imaging. The overall agreement for detection of viable myocardium was 81% between FDG-dPET (AC) and FDG-GCPET (AC) and 74% between FDG-dPET (AC) and FDG-GCPET (NC).

CONCLUSION

This study suggests that the assessment of myocardial metabolism by means of FDG is feasible with a coincidence based gamma camera equipped with 1 inch thick NaI crystals if AC is performed. The results reveal a close concordance and agreement between FDG-dPET (AC) and FDG-GCPET (AC) as compared to FDG-GCPET (NC).

FDG gamma camera PET equipped with one inch crystal and XCT

Metabolic imaging with 2-[fluorine-18]-fluoro- 2-deoxy-D-glucose (FDG) is actually considered as the best method to detect and quantitatively assess myocardial tissue viability. The aim of this study was to investigate the accuracy of FDG gamma camera positron emission tomography (GCPET) imaging equipped with one inch NaI crystals in comparison to FDG dedicated PET (dPET) imaging as a „gold standard“ in phantom and clinical studies. Patients, methods: Nineteen patients with coronary artery disease (CAD) underwent both imaging modalities. Phantom and clinical GCPET imaging were performed with a dual-headed, coincidence based gamma camera equipped with 1 inch thick NaI crystals and an x-ray tube (XCT) for attenuation correction (AC), as well as with a dedicated PET scanner with AC. 99mTc tetrofosmin single-photon emission tomography (SPET) studies were performed for assessment of myocardial perfusion, with AC. Results: Phantom studies showed a significant relation in segmental activity between FDG imaging with AC using GCPET and dPET (r = 0.91, p <0.001). In clinical studies with AC correlation coefficients of mean segmental FDG uptake and regional defect size were r = 0.87 (p <0.0001) and r = 0.83 (p <0.0001), respectively. In regional analysis close agreement was even found in the most attenuated regions of the heart if AC was used in GCPET imaging. The overall agreement for detection of viable myocardium was 81% between FDG-dPET (AC) and FDG-GCPET (AC) and 74% between FDG-dPET (AC) and FDG-GCPET (NC). Conclusion: This study suggests that the assessment of myocardial metabolism by means of FDG is feasible with a coincidence based gamma camera equipped with 1 inch thick NaI crystals if AC is performed. The results reveal a close concordance and agreement between FDG-dPET (AC) and FDG-GCPET (AC) as compared to FDG-GCPET (NC).

Attenuation correction for myocardial perfusion imaging. A comparison between SPECT and PET imaging by polar map analysis

AIM

We investigated the impact of photon attenuation in myocardial perfusion imaging with SPECT and PET in patients with coronary artery disease. In fact, the regional tracer distribution can be quantitatively assessed by polar map analysis if the effects of photon attenuation are accounted for. PET imaging permits accurate measurement of and correction for photon attenuation, whereas results of attenuation correction in SPECT imaging have been inconsistent.

PATIENTS, METHODS

We compared photon attenuation in resting perfusion imaging studies with SPECT ((99m)Tc-sestamibi) and PET ((13)N-ammonia) from 21 patients. Transaxial images were reconstructed with and without attenuation correction and reoriented into short axis images. Polar map analysis was utilized to generate regional tracer uptake in six anatomical segments.

RESULTS

Average segmental photon attenuation calculated as the ratio of counts in corrected and uncorrected images was 7.2 +/- 1.4 in SPECT and 14.0 +/- 3.1 in PET imaging (p < 0.01). This attenuation factor was significantly related to body mass index for both methods (p < 0.001). While attenuation correction for SPECT imaging did compensate for attenuation effects in the inferior wall (from -15% to +6% vs. PET), relative tracer uptake in the anterior wall in SPECT images was significantly reduced after attenuation correction (from -2% to -18% vs. PET, p < 0.01).

CONCLUSION

Differential effects of attenuation correction for myocardial SPECT perfusion imaging need to be considered when algorithms designed to compensate effects of photon attenuation in SPECT imaging are employed in clinical practice.

13N-ammonia rest/stress PET

Aim: Hyperhomocysteinaemia (Hhcy) is known to be an independent risk factor for vascular disease. Coronary flow reserve (CFR) measured by positron emission tomography (PET) is a sensitive method to monitor the effects of pharmacologic interventions in Hhcy. We assessed coronary vascular reactivity by PET in patients with coronary artery disease (CAD) dependent on their homocysteine (Hcy) levels before and under high dose folic acid supplementation therapy (FAST). Patients, methods: Twelve patients with CAD underwent rest/adenosine 13N-ammonia PET for quantification of myocardial blood flow (MBF) and CFR before and after nine weeks FAST (10 mg/day). Results: Folate levels increased from 21 ± 6 to 210 ± 34 μg/l (+900%, p <0.0001) while Hcy levels decreased from 12.1 ± 3.6 to 9.1 ± 3.1 μmol/l (–25%; p <0.01). Global resting MBF remained nearly unchanged after FAST, while stress MBF (from 2.61 ± 0.93 to 3.25 ± 1.15 ml/ g/min; p = 0.05) and CFR (from 3.00 ± 0.76 to 3.72 ± 0.93 ml/g/min; p <0.05; +24%) significantly increased in patients with normal and elevated Hcy levels (cut off 12 μmol/l). An inverse relation was found between Hcy and CFR (R = –0.53; p = 0.08) and between Hcy and MBF at rest (R = –0.62; p < 0.05) at baseline conditions, not persisting after FAST. Conclusion: Coronary vascular reactivity can be improved by FAST in patients with CAD and normal or elevated Hcy levels. FAST might lower an increased cardiovascular risk in CAD patients possibly by mechanisms that are not related to Hcy.

13N-ammonia rest/stress PET: folic acid improves global coronary vasoreactivity in coronary artery disease patients with normal or elevated homocysteine levels

AIM

Hyperhomocysteinaemia (Hhcy) is known to be an independent risk factor for vascular disease. Coronary flow reserve (CFR) measured by positron emission tomography (PET) is a sensitive method to monitor the effects of pharmacologic interventions in Hhcy. We assessed coronary vascular reactivity by PET in patients with coronary artery disease (CAD) dependent on their homocysteine (Hcy) levels before and under high dose folic acid supplementation therapy (FAST).

PATIENTS, METHODS

Twelve patients with CAD underwent rest/adenosine (13) N-ammonia PET for quantification of myocardial blood flow (MBF) and CFR before and after nine weeks FAST (10 mg/day).

RESULTS

Folate levels increased from 21 +/- 6 to 210 +/- 34 microg/l (+900%, p < 0.0001) while Hcy levels decreased from 12.1 +/- 3.6 to 9.1 +/- 3.1 micromol/l ( - 25%; p < 0.01). Global resting MBF remained nearly unchanged after FAST, while stress MBF (from 2.61 +/- 0.93 to 3.25 +/- 1.15 ml/g/min; p = 0.05) and CFR (from 3.00 +/- 0.76 to 3.72 +/- 0.93 ml/g/min; p < 0.05; +24%) significantly increased in patients with normal and elevated Hcy levels (cut off 12 micromol/l). An inverse relation was found between Hcy and CFR (R = - 0.53; p = 0.08) and between Hcy and MBF at rest (R = - 0.62; p < 0.05) at baseline conditions, not persisting after FAST.

CONCLUSION

Coronary vascular reactivity can be improved by FAST in patients with CAD and normal or elevated Hcy levels. FAST might lower an increased cardiovascular risk in CAD patients possibly by mechanisms that are not related to Hcy.

Online myocardial viability assessment in the catheterization laboratory via NOGA electroanatomic mapping: Quantitative comparison with thallium-201 uptake

BACKGROUND

The aim of this prospective study was to investigate the concordance between quantitative resting (201)Tl uptake as an established myocardial viability index and the electrical activity of the heart, determined by NOGA nonfluoroscopic electroanatomic mapping.

METHODS AND RESULTS

The myocardial resting and late resting thallium uptakes of 384 myocardial segments from 32 patients (27 males aged 65+/-8 years) with previous myocardial infarction and chronic stable angina were compared with unipolar voltage potentials and local shortening of the left ventricle as assessed by electroanatomic mapping. The quantitative thallium uptake data were analyzed by polar map analysis by division into 12 comparable myocardial segments, as represented in electroanatomic mapping images. Unipolar voltage potentials exhibited a significant logarithmic correlation with both resting and late resting thallium uptake (attenuation corrected: r=0.660 and r=0.744; non-attenuation corrected: r=0.623 and r=0.721). Receiver operator characteristic analyses revealed unipolar voltage cutoff points of 12.0 mV (predictive accuracy 0.853, P< 0.001; sensitivity/specificity 81%) for normal myocardium and 6.4 mV (predictive accuracy 0.901, P< 0.001; sensitivity/specificity 82%) for nonviable myocardium assessed by attenuation-corrected (201)Tl late resting images and of 12.7 mV (predictive accuracy 0.822, P<0.001; sensitivity/specificity 75%) and 6.5 mV (predictive accuracy 0.808, P<0.001; sensitivity/specificity 73%) for non-attenuation-corrected late resting (201)Tl images.

CONCLUSIONS

These results indicate that the unipolar voltage potentials obtained by electroanatomic mapping correlate well with standard quantitative late resting (201)Tl imaging for the evaluation of myocardial viability; thus, NOGA endocardial mapping provides useful "online" data at the time of catheterization, especially when information from other methods for viability assessment is unavailable.

Automated assessment of dipyridamole 201Tl myocardial SPECT perfusion scintigraphy by case-based reasoning

This study evaluated the diagnostic accuracy of case-based reasoning (CBR) to automatically detect significant coronary artery disease from dipyridamole 201Tl myocardial SPECT perfusion scintigrams.

METHODS

The study population included 240 patients (182 men, 58 women; mean age +/- SD, 61 +/- 12 y) on whom coronary angiography and perfusion scintigraphy were performed within 6 +/- 11 d of each other. The patients were divided into two groups according to the presence or absence of significant coronary disease in any major coronary vessel. Regional myocardial tracer uptake was observed in 84 segments by polar map analysis. For each scintigraphic image, a CBR algorithm based on a similarity metric was used to identify similar scintigraphic images within the case library. The angiographic results of these similar cases were used to obtain the CBR reading, which was compared with the true angiographic results. Myocardial scintigrams were also analyzed by a first-generation Cedars-Sinai (CS) method, including a comparison with a reference database, and by the visual analysis of an expert reader.

RESULTS

By receiver-operating-characteristic analysis, the diagnostic accuracy of CBR was not different from the interpretation by the CS algorithm and from visual interpretation (P = not significant [NS]). For detection of significant coronary disease, the respective sensitivities at 50% and 80% specificity were 90% and 67% for CBR, 88% and 65% for CS polar map analysis, and 91% and 74% for visual interpretation. For the detection of coronary disease in the vascular territories assigned to the left anterior descending and the right coronary arteries, CBR and CS polar map analysis showed similar diagnostic accuracy (P = NS). However, for detection of disease in the circumflex artery, CS polar map analysis was slightly better than CBR (P = 0.03).

CONCLUSION

Automated interpretation of dipyridamole 201Tl myocardial SPECT perfusion images by CBR has diagnostic accuracy similar to that of visual interpretation or CS analysis. Thus, use of a case library that includes a variety of normal and abnormal perfusion images does not appear to have greater diagnostic power than use of reference limits.

Longitudinal straightening effect of stents is an additional predictor for major adverse cardiac events. Austrian Wiktor Stent Study Group and European Paragon Stent Investigators

OBJECTIVES

The aim of this study was to perform an investigation of the effects of the longitudinal straightening of coronary arteries by stents and the possible association with major adverse cardiac events (MACE) (primary end point) and angiographic restenosis (secondary end point).

BACKGROUND

Stent deployment straightens a tortuous artery, and any consequent arterial longitudinal stretch may contribute to MACE and stent restenosis severity.

METHODS

Clinical, qualitative and quantitative angiographic data on 404 patients with single stent implantation were subjected to multivariate nominal logistic regression analysis for the prediction of MACE. The predictive accuracy, sensitivity and specificity values and cut-off points of the continuous variables were determined via receiver operating characteristics curves. The longitudinal straightening effect of stents was characterized through the changes in vessel angle (defined by the tangents to the proximal and distal parts of the stenoses/stents).

RESULTS

Follow-up angiography on 354 patients revealed 73 cases of stent restenosis (> or =50% diameter stenosis). Coronary bypass surgery was performed in 4 patients and repeated percutaneous transluminal coronary angioplasty in 56 patients; acute myocardial infarction (AMI) occurred in 2 patients, and 4 patients died during the follow-up. The overall incidence of MACE (death, AMI and revascularization) was 16.3% (66 patients). The best predictive accuracies and sensitivities/specificities of factors indicative of MACE were found for the minimal lumen diameter (MLD) at follow-up (predictive accuracy: 0.9305, sensitivity/specificity: 86.6%), the post-stent MLD (0.773, 77.2%), the percent diameter stenosis (%DS) at follow-up (0.9432, 87.1%), the prestent vessel angulation (0.6797, 68.2%) and the poststent changes in vessel angulation (0.6279, 62.2%). Multivariate nominal logistic regression analysis demonstrated that a poststent MLD < or =2.63 mm (p = 0.0017, odds ratio [OR] = 17.961, 95% confidence interval [CI] = 17.45-20.428), an MLD at follow-up < or =1.7 mm (p = 0.0059, OR = 11.880, 95% CI = 11.490-14.093), a %DS at follow-up > or =42.2% (p = 0.0000, OR = 49.553, 95% CI = 48.024-53.507), a prestent vessel angulation > or =33.5 degrees (p = 0.0477, OR = 5.404, 95% CI = 5.382-7.142) and poststent changes in vessel angulation > or =9.1 degrees (p = 0.0026, OR = 19.161, 95% CI = 18.562-21.750) were significant predictors for MACE. Multiple linear regression revealed that the poststent MLD (multivariate p = 0.0001), the MLD at follow-up (p = 0.0000), the prestent vessel angulation (p = 0.0431) and the changes in vessel angulation after stent implantation (p = 0.0316) were significant independent variables predicting angiographic stent restenosis severity.

CONCLUSIONS

The longitudinal straightening effect of coronary artery stents contributes significantly to the occurrence of MACE and angiographic restenosis, and this finding may have an impact on future stent design.