bluuebunny/crossref_metadata_2025 huggingface dataset:
Periodontal Status of Patients With Dentin Dysplasia Type I: Report of Three Cases Within a Family
Authors: Da Rós Gonçalves Lorena , Oliveira Cristiana Aroeira G.R. , Holanda Rose , Silva‐Boghossian Carina M. , Colombo Ana Paula Vieira , Maia Lucianne Cople , Feres‐Filho Eduardo Jorge
Published: July 2008

Background: Dentin dysplasia type I (DDI) is a rare hereditary disturbance of dentin formation. It is characterized by clinically normal–appearing crowns; obliteration of pulp chambers; and short, blunted and malformed roots that are commonly associated with periodontal attachment loss (PAL). In this context, we report three cases within a family with similar clinical and radiographic features of DDI but with differing microbiologic and periodontal conditions.

Methods: A 42‐year‐old white female and her two daughters (25 and 10 years of age) presented with a diagnosis of DDI. Probing depth (PD), clinical attachment level (CAL), visible plaque, and bleeding on probing (BOP) were recorded. Subgingival biofilm samples were randomly collected and analyzed by checkerboard DNA‐DNA hybridization.

Results: The mother presented 34.9% of sites with PD ≥4 mm, 41.3% of sites with CAL ≥4 mm, and 57% of sites with BOP; both daughters presented no sites with PD or CAL >3 mm and <10% of sites with BOP. Microbiologic analysis detected Gemella morbillorum, Neisseria mucosa, and Staphylococcus aureus in ≥50% of the mother's samples. The daughters showed high levels (>104 bacterial cells) of some periodontopathic bacteria, including members of the red (Porphyromonas gingivalis) and orange (Fusobacterium periodonticum and F. nucleatum polymorphum) complexes and beneficial species of the yellow (Streptococcus gordonii) and purple (Veillonella parvula) complexes. The mother presented high mean levels only for four tested species (N. mucosa, Prevotella melaninogenica, Treponema denticola, and V. parvula).

Conclusion: A combination of radiographs, microbiologic analysis, and preventive professional monitoring care is important to avoid PAL and to provide oral health in patients with DDI.
A Comparative Analysis of Bone Formation Induced by Human Demineralized Freeze‐Dried Bone and Enamel Matrix Derivative in Rat Calvaria Critical‐Size Bone Defects
Authors: Intini Giuseppe , Andreana Sebastiano , Buhite Robert J. , Bobek Libuse A.
Published: July 2008

Background: Human demineralized freeze‐dried bone allograft (DFDBA) and enamel matrix derivative (EMD) have been used with varying success for the treatment of bone and periodontal defects. The purpose of this study was to compare qualitatively and quantitatively the bone formation induced by DFDBA and EMD to that of a positive control, recombinant human bone morphogenetic protein 2 (rhBMP‐2), in the 8‐mm rat calvaria critical‐size bone defect.

Methods: Five groups of five rats each were used. The two test groups were DFDBA and EMD. A negative control consisted of a defect without any biomaterial implanted, a positive control consisted of a defect filled with collagen carrying rhBMP‐2, and a non‐surgical control consisted of the intact rat calvaria. Eight weeks after implantation of the biomaterials, histologic analysis was used for qualitative assessments and microcomputed tomography was used for quantitative assessments of bone formation. Statistical evaluation was performed by analysis of variance followed by the Fisher's least significant difference multiple‐comparison test.

Results: In the negative control and EMD groups, the histologic analysis showed no bone formation within the center of the defect and limited bone repair at its margins. In the DFDBA group, granules of DFDBA were still present 8 weeks after implantation, and a limited degree of osteoinduction was seen at the center of the defect. The microcomputed tomography quantitative analysis showed a limited capacity of DFDBA and EMD to induce bone formation, and no statistically significant difference was detected among DFDBA, EMD, and the negative control. On the contrary, the positive control (rhBMP‐2) consistently showed regeneration of bone throughout the critical‐size defects.

Conclusion: Unlike rhBMP‐2, DFDBA and EMD had limited ability to induce bone formation in the rat calvaria critical‐size bone defect; therefore, they may not be effective as bone‐regenerative therapy for critical‐size defects.
Ultrashort Sintered Porous‐Surfaced Dental Implants Used To Replace Posterior Teeth
Authors: Deporter Douglas , Ogiso Bunnai , Sohn Dong‐Seok , Ruljancich Kevin , Pharoah Michael
Published: July 2008

Background: This retrospective multicenter report provides data from a case series of partially edentulous subjects treated with an ultrashort (5‐mm‐long) sintered porous‐surfaced (SPS) dental implant.

Methods: The implant used had a tapered truncated cone shape, was 5‐mm long, and had a maximal coronal diameter of 5 mm. Twenty‐six implants were placed in 20 subjects to replace primarily maxillary and mandibular molar teeth. Submerged primary healing was used. Nine implants were restored with single crowns, one carried a single cantilever, and the remaining 16 implants were part of fixed implant‐supported bridges, generally as the most distal abutment.

Results: After functional periods of 1 to 8 years, two maxillary implants failed, giving maxillary and mandibular failure rates of 14.3% and 0%, respectively.

Conclusion: The results of this case series suggest that an SPS, press‐fit, tapered dental implant with a length of 5 mm and a maximal coronal diameter of 5 mm should be investigated further as a solution for the management of highly resorbed posterior sites in partial edentulism, particularly in the mandible.
Clinical and Laboratory Evaluations of Non‐Surgical Periodontal Treatment in Subjects With Diabetes Mellitus
Authors: Cruz Gabriela Alessandra da , de Toledo Sergio , Sallum Enilson Antonio , Sallum Antonio Wilson , Ambrosano Gláucia Maria Bovi , de Cássia Orlandi Sardi Janaina , Cruz Sérgio Eduardo Braga da , Gonçalves Reginaldo Bruno
Published: July 2008

Background: The aim of this study was to evaluate the clinical and laboratory changes 3 months after full‐mouth scaling and root planing in subjects with and without diabetes mellitus.

Methods: This study was performed using 10 subjects with type 2 diabetes mellitus who required insulin therapy (DM) and 10 healthy adult control subjects (NDM) with generalized chronic periodontal disease. Both groups were treated with full‐mouth scaling and root planing and given oral hygiene instructions. Clinical parameters, including plaque index (PI), gingival index (GI), probing depth (PD), gingival recession (GR), and clinical attachment level (CAL), were measured at four sites per tooth. Subgingival plaque samples were obtained from sites with the deepest PD (≥5 mm) and with furcations in each subject. Samples were also tested for the presence of Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans), Porphyromonas gingivalis, and Tannerella forsythia (previously T. forsythensis) by polymerase chain reaction. Glycemic control (glycosylated hemoglobin [HbA1c] and fasting glucose levels) and clinical and microbiologic assessments were recorded at baseline and 3 months after periodontal treatment.

Results: Data revealed statistical changes (P ≤0.05; analysis of variance [ANOVA]) in clinical variables (PI, GI, PD, GR, and CAL) between baseline and 3 months in both groups. Conversely, no improvement in the fasting glucose level or glycosylated hemoglobin (P ≤0.05; ANOVA) was found after treatment. Besides some reduction in the bacterial frequency 3 months after treatment, no statistically significant difference was found between the groups.

Conclusion: Clinical and laboratory responses were similar in DM and NDM groups 3 months after full‐mouth scaling and root planing.
Histologic and Elemental Microanalytical Study of Anorganic Bovine Bone Substitution Following Sinus Floor Augmentation in Humans
Authors: Traini Tonino , Degidi Marco , Sammons Rachel , Stanley Paul , Piattelli Adriano
Published: July 2008

Background: Histologic data regarding the use of anorganic bovine bone (ABB) in humans are scarce. This study was a histologic evaluation and an examination of the elemental composition of ABB particles and adjacent bone in humans.

Methods: Ten biopsies were retrieved 20 months after maxillary sinus augmentation in five patients. The investigation was carried out using light microscopy in brightfield, fluorescence, and circularly polarized light and scanning electron microscopy (SEM) with energy‐dispersive x‐ray spectroscopy.

Results: The regenerated tissue consisted of 38% ± 2.1% newly formed bone, 36% ± 1.3% marrow spaces, and 29% ± 1.8% residual ABB particles. Under polarized light, the newly formed bone was characterized by randomly oriented collagen fibers. Under fluorescence, the biomaterial showed close apposition to bone; under SEM, several projections of newly formed bone were seen penetrating the ABB particles. ABB and bone were distinguished by the lighter gray color of the biomaterial in back‐scattered electron images; ABB particles were surrounded and linked by newly formed bone. Elemental analysis gave average calcium/phosphorus ratios (atomic %) ∼1.9 for ABB and 1.4 for bone. Relatively high concentrations of calcium and phosphorus in the biomaterial decreased gradually toward the interface with bone.

Conclusion: The persistence of ABB in the human tissue after 20 months might have been related to the relatively high calcium content of the biomaterial as well as the absence of proteins.
Gingival Crevicular Fluid Alkaline Phosphatase Activity Reflects Periodontal Healing/Recurrent Inflammation Phases in Chronic Periodontitis Patients
Authors: Perinetti Giuseppe , Paolantonio Michele , Femminella Beatrice , Serra Emanuela , Spoto Giuseppe
Published: July 2008

Background: Roles for host enzymes as diagnostic indicators of periodontal status in gingival crevicular fluid (GCF) have been proposed. One of these host enzymes is alkaline phosphatase (ALP), the GCF activity of which has been associated with periodontal inflammation. Thus, the present study aimed to improve our understanding of how the healing of chronic periodontitis following scaling and root planing (SRP) affects GCF ALP activity after 15 and 60 days.

Methods: Sixteen systemically healthy subjects (aged 35 to 61 years) with moderate to advanced generalized chronic periodontitis were recruited. In each subject, paired pockets with probing depths (PDs) ≥4 mm that were located in two symmetric quadrants were chosen. These sites were randomized at the split‐mouth level, with half receiving SRP treatment and the other half left untreated. Ninety‐two pockets were included in the study. Clinical examinations were performed at baseline (prior to SRP) and after 15 and 60 days; information recorded included the presence of plaque, PD, clinical attachment level (CAL), and bleeding on probing. GCF was collected from each pocket included in the study at the three time points.

Results: A large and significant decrease in GCF ALP activity was seen 15 days after SRP, concomitant with an improvement in clinical parameters. After 60 days, an increase in GCF ALP activity back to baseline levels was recorded along with further improvements in clinical parameters. Moreover, in the SRP pockets with initial PDs >6 mm, the CAL gains between days 15 and 60 were significantly associated with changes in GCF ALP activity over the same time interval.

Conclusions: The decrease in GCF ALP activity at 15 days corresponded to a decrease in clinical signs of inflammation; in contrast, the increase in GCF ALP activity at 60 days seemed to be related to subclinical recurrent inflammation or further healing/remodeling of the periodontal tissue. Therefore, GCF ALP reflects the short‐term periodontal healing/recurrent inflammation phases in chronic periodontitis patients.
Case Reports of a New Syndrome Associating Gingival Fibromatosis and Dental Abnormalities in a Consanguineous Family
Authors: Martelli‐Júnior Hercílio , Bonan Paulo Rogério Ferreti , dos Santos Luis Antônio Nogueira , Santos Suelleng Maria Cunha , Cavalcanti Marcelo Gonçalves , Coletta Ricardo D.
Published: July 2008

Background:Gingival fibromatosis (GF) is characterized by fibrotic enlargement of the gingiva that can be inherited as an isolated trait (named hereditary gingival fibromatosis) or as a component of a syndrome. This article reports one kindred affected by a syndrome characterized by GF associated with dental abnormalities (DA) including generalized thin hypoplastic amelogenesis imperfecta (AI).

Methods:To characterize the pattern of inheritance and the clinical features, 70 family members were examined. Hematoxylin and eosin staining, immunohistochemistry, and scanning electronic microscopy (SEM) were performed to identify the alterations on gingiva, teeth, and dental follicles.

Results:Examination of the family pedigree demonstrated multiple consanguineous first‐cousin marriages and an autosomal recessive trait of inheritance. Four members demonstrated mild GF in association with DA, including generalized thin hypoplastic AI, intrapulpal calcifications, delay of tooth eruption, and pericoronal radiolucencies involving unerupted teeth. One of those four patients also had mental retardation (MR). MR as an isolated feature was observed in six members, whereas isolated GF was found in one individual. A combination of gingivectomy and gingivoplasty followed by regular dental procedures were performed in these patients. Histologic examination of the gingival enlargement revealed a dense connective tissue containing myofibroblasts, islands of odontogenic epithelium, and calcified psammomatous deposits, which resembled cementicle‐like structures by SEM. Pericoronal lesions also showed calcified psammomatous deposits in association with islands of odontogenic epithelium. Enamel ultrastructure analysis revealed normal surface alternating with irregular and porous areas.

Conclusion:To the best of our knowledge, these cases represent a new syndrome within the spectrum of those including GF.
Thrombin Activates Ras‐CREB/ATF‐1 Signaling and Stimulates c‐fos, c‐jun, and c‐myc Expression in Human Gingival Fibroblasts
Authors: Chan Chiu‐Po , Chang Mei‐Chi , Wang Ying‐Jan , Chen Lin‐I , Tsai Yi‐Ling , Lee Jang‐Jaer , Jia Hsi‐Wei , Jeng Jiiang‐Huei
Published: July 2008

Background: Protease‐activated receptors (PARs) can be stimulated by thrombin and other proteases generated by periodontal pathogens. Activation of PARs in gingival fibroblasts (GFs) can modulate wound healing and inflammatory responses in gingival tissues.

Methods: The mRNA expression of PARs and early responsive genes in GFs and other oral cells was studied by reverse transcription‐polymerase chain reaction. Western blotting was used to study the activation of p38 and cAMP responsive element binding protein (CREB)/activating transcription factor (ATF)‐1 as well as Ras.

Results: GFs, dental pulp cells, and buccal mucosal fibroblasts expressed PAR‐1 and −3 receptors, whereas gingival keratinocytes expressed PAR‐1 and −2 receptors. Stimulation of GFs by thrombin rapidly activated Ras signaling and the phosphorylation of CREB/ATF‐1 and p38. Thrombin also stimulated the expression of c‐fos in GFs within 1 hour of exposure. Stimulation of c‐jun mRNA expression showed biphasic responses with two peaks after 1 and 8 hours of exposure. Elevated c‐myc expression in GFs by thrombin was noted after 2 hours of exposure. Moreover, the stimulation of c‐fos and c‐myc mRNA expression by thrombin can be attenuated by D‐Phe‐Pro‐ArgCH2Cl, a serine‐proteinase inhibitor.

Conclusions: PAR activation during gingival wounding or inflammation may stimulate Ras‐CREB/ATF‐1 signaling and c‐fos, c‐jun, and c‐myc expression. This might be due to the proteinase activity of thrombin. These signaling events are important for wound healing and inflammatory responses in gingival tissues.
Strawberry‐Like Gingival Tumor as the First Clinical Sign of Wegener's Granulomatosis
Authors: Hernández Gonzalo , Serrano Cristina , Porras Lourdes , Lopez‐Pintor Rosa , Rubio Lourdes , Yanes Jaime
Published: July 2008

Background: Wegener's granulomatosis (WG) is a complex disease, characterized by a necrotizing vasculitis that usually involves the upper airways, lungs, and kidneys; occasionally, other organs may also be affected. Because of the severity and rapid progression of the disease, early diagnosis and treatment are critical; this type of vasculitis is potentially fatal if left unchecked.

Methods: A 64‐year‐old woman presented with a chief complaint of a gingival mass that had appeared 2 months before and had grown rapidly. In the previous months she complained of malaise without weight loss. An intraoral examination revealed the presence of a solitary gingival mass, 2 cm in diameter, affecting the area above the upper central incisors. The lesion displayed a granular, erythematous, speckled surface with petechiae, characteristic of WG.

Results: A biopsy of the lesion, a thoracic computed tomography, and the presence of high titers of antineutrophil cytoplasmic antibodies (ANCA) in the blood established the diagnosis of WG. An initial combination therapy of prednisone and cyclophosphamide successfully abated most of the patient's symptoms.

Conclusions: The occurrence of an extremely rare tumor‐like form of strawberry gingiva was the primary clinical sign that led to a diagnosis of WG. This case emphasizes the important role of the dentist in the diagnosis of this potentially fatal disease.
Detection of Bone Loss With Different X‐Ray Techniques in Periodontal Patients
Authors: Kim Ti‐Sun , Obst Christian , Zehaczek Sven , Geenen Claudia
Published: July 2008

Background: Intraoral radiographs can aid in formulating a more accurate diagnosis of periodontal disease. However, it must be considered whether a comparable amount of information can be obtained with modern panoramic radiographs. The aim of this study was to determine to what degree the diagnosable amount of bone loss in patients with aggressive periodontitis or severe chronic periodontitis depends on the type of x‐ray technique used.

Methods: A total of 110 subjects (63 females) were included in this study. The inclusion criteria were the diagnosis of aggressive periodontitis (N = 49) or severe chronic periodontitis (N = 61). In all patients, panoramic radiographs (panoramic) and intraoral films of all regions (eight to 10 single exposures) were available. Analysis of the panoramic and intraoral films was carried out with a computer‐assisted technique for linear measurement. The amount of bone loss in reference to the alveolar crest (AC) and bottom of the bony defect (BD) was determined as a percentage of total root length.

Results: Depending on the examined tooth and reference point, 47.01% to 81.89% of all subjects showed differences between intraoral and panoramic measurements that were ≤10% of the total root length. For cemento‐enamel junction–AC measurements, differences between intraoral and panoramic measurements that were >10% of the total root length were found predominantly in the upper molar and premolar regions. In the mandible, differences between intraoral and panoramic measurements that were >10% of the total root length were observed for BD and AC at the mesial contour of the central incisor.

Conclusions: A preorientation with respect to the expected bone loss is possible using panoramic radiographs. Additional intraoral films might be helpful where rapid changes of bone level are expected (e.g., aggressive periodontitis).
Clinical Outcome of Immediately Loaded Dental Implants Bioactivated With Plasma Rich in Growth Factors: A 5‐Year Retrospective Study
Authors: Anitua Eduardo , Orive Gorka , Aguirre José Javier , Andía Isabel
Published: July 2008

Background: The aims of this study were to describe a procedure for the immediate loading of dental implants, evaluate the long‐term survival rates of 1,139 immediately loaded dental implants, and analyze the influence of different factors on implant survival.

Methods: A retrospective cohort study design was used. A total of 241 patients received 1,139 immediately loaded implants between 2001 and 2005 in Vitoria, Spain. All implants were placed by one experienced surgeon, and rehabilitations were done by four prosthodontists. Each implant failure was analyzed carefully. The potential influence of demographic, clinical, and surgery‐dependent factors and prosthetic variables on implant survival was studied. Implant survival was analyzed using a life‐table analysis.

Results: The overall survival rates were 99.3%, 96.8%, and 96.9% for the implant‐, surgery‐, and patient‐based analyses, respectively. The mean follow‐up period was 28 ± 15 months. Five of 1,139 implants were lost during the observation period. No variable studied was statistically associated with implant failure.

Conclusion: Based on these results, the procedure described for the immediate loading of implants can be considered safe and predictable if used under strict clinical protocols.
Alveolar Process Anabolic Activity in C3H/HeJ and C57BL/6J Inbred Mice
Authors: Meta Isaac F. , Fernandez Soledad A. , Gulati Parul , Huja Sarandeep S.
Published: July 2008

Background: The purpose of this study was to characterize bone activity of the alveolar process in C3H/HeJ (C3H) and C57BL/6J (B6) inbred mice. Based on observations in other animal species, we hypothesized that the bone‐formation rate/bone surface (BFR/BS) is greater in the alveolar process compared to the body of the mandible and that the bone anabolic activity is greater in the alveolar process of the mandible than in the maxilla. We also examined the alveolar process of C3H and B6 mice for the presence of secondary osteons.

Methods: Jaws from 17‐week‐old C3H and B6 female mice (N = 15/group) were harvested. Histomorphometric parameters were evaluated in sections from the alveolar process, each of which included at least one molar root.

Results: In C3H and B6 mice, BFR/BS was not significantly different (P >0.05) between the alveolar process and the body of the mandible. In C3H mice, BFR/BS was significantly greater (P = 0.05) in the mandible compared to the maxilla. BFR/bone volume (BV) was not significantly different (P >0.05) between C3H mandible and maxilla. In the B6 inbred mouse, BFR/BS and BFR/bone volume (BV) were not significantly different (P >0.05) between jaws. After analyzing 165 bone sections, we identified 25 secondary osteons.

Conclusions: The surface anabolic activity was not different between the body and the alveolar process of the mandible. The surface activity was greater in the C3H mandible than in the maxilla. Although secondary osteonal bone remodeling existed in the C3H and B6 alveolar bone, this process was not a consistent finding.
The Effects of a Calorie‐Reduced Diet on Periodontal Inflammation and Disease in a Non‐Human Primate Model
Authors: Branch‐Mays Grishondra L. , Dawson Dolphus R. , Gunsolley John C. , Reynolds Mark A. , Ebersole Jeffrey L. , Novak Karen F. , Mattison Julie A. , Ingram Donald K. , Novak M. John
Published: July 2008

Background: Low‐calorie diets are commonplace for reducing body weight. However, no information is available on the effects of a reduced‐calorie diet on periodontal inflammation and disease. The purpose of this study was to evaluate the clinical effects of a long‐term calorie‐restriction (CR) diet on periodontitis in an animal model of periodontitis.

Methods: Periodontitis was induced in 55 young, healthy, adult rhesus monkeys (Macaca mulatta) by tying 2.0 silk ligatures at the gingival margins of maxillary premolar/molar teeth. Animals on a CR diet (30% CR; N = 23) were compared to ad libitum diet controls (N = 32). Clinical measures, including the plaque index (PI), probing depth (PD), clinical attachment level (CAL), modified gingival index (GI), and bleeding on probing (BOP) were recorded at baseline and 1, 2, and 3 months after ligature placement.

Results: Significant effects of CR were observed on the development of inflammation and the progression of periodontal destruction in this model. Compared to controls, CR resulted in a significant reduction in ligature‐induced GI (P <0.0001), BOP (P <0.0015), PD (P <0.0016), and CAL (P <0.0038). Periodontal destruction, as measured by CAL, progressed significantly more slowly in the CR animals than in the controls (P <0.001).

Conclusions: These clinical findings are consistent with available evidence that CR has anti‐inflammatory effects. Moreover, these experimental findings are the first observations, to the best of our knowledge, that CR dampens the inflammatory response and reduces active periodontal breakdown associated with an acute microbial challenge.
Factors Controlling the Membrane Efficiency of Shales When Interacting With Water-Based and Oil-Based Muds
Authors: Zhang Jianguo , Al-Bazali Talal M. , Chenevert Martin E. , Sharma Mukul M.
Published: July 2008

This paper presents a comprehensive set of experimental data for the membrane efficiency of four shales when interacting with different water-based and oil-based muds. Pressure transmission tests were used to measure the membrane efficiency using three different cations and two different anions at different concentrations (water activities).

It was found that the measured membrane efficiencies of shales, when exposed to salt solutions, were low—ranging from 0.18% to 4.23%. Useful correlations are presented between the membrane efficiency and other shale properties. Results suggest that the membrane efficiency of shales is directly proportional to the ratio of the cation exchange capacity and permeability of shales. Higher cation exchange capacities and lower permeabilities correlate very well with higher membrane efficiencies. Moreover, the ratio of the hydrated solute (ion) size to shale pore throat determines a shale's ability to restrict solutes from entering the pore space and controls its membrane efficiency. Cations and anions with large hydrated radii yielded higher membrane efficiencies, compared to ions with small hydrated diameters. Thus, the formulation of drilling fluids must take into account the types of cation and anion in the water-based fluid.

It was also found that the membrane efficiency of oil-based muds was high, however, these membrane efficiencies were not 100 % as postulated by many researchers.
Improved Prediction of Shallow Sediment Fracturing for Offshore Applications
Authors: Kårstad E. , Aadnoy B. S.
Published: July 2008

The complexity of oil and gas wells has increased significantly during the past decades. In addition to improved equipment, a better understanding of the subsurface environment is required to efficiently drill these wells.

Fracturing, as related to circulation losses, is a contiuous challenge when drilling these wells. For that reason two modeling activities have been pursued in Norway during the past decades: 1) establishing a fracturing model for shallow sediments offshore, and 2) developing a fracture model for deepwater drilling.

Data from seabed investigations as well as from conductor and surface casings were collected and normalized for varying water depths. This model works well and has been used for many years. When deepwater drilling started in 1997, the same concept was applied, and the results show that the same type of model also applies for deepwater drilling. Wells from Norway, UK, the Gulf of Mexico, Angola, and Brazil have been analyzed and show remarkably similar behavior when the water depth is considered.

This paper brings this work further by presenting a generalized fracture model for shallow sediments in relaxed depositional environments. Data normalization is a key method for making the fracture model applicable for all water depths. Normalization methods are presented so fracture data can be converted to other water depths and serve as a prognosis for new wells (based on rig floor elevation, water depth, differences in overburden stresses, and on mud properties).

Several field cases are presented with water depths ranging from 380 m to 1350 m, demonstrating the wide applicability of the new model.

It is shown that the generalized fracture model for shallow sediments provides a good correlation with an error within a few percent.
Cementing Under Pressure in Well-Kill Operations: A Case History From the Eastern Mediterranean Sea
Authors: Johnstone Kristian , Gill Alex , Conlon Tom , Bahr Mahdy , Waheed Arshad
Published: July 2008

Well control can be an unpleasant experience. In its initial stages the problem often appears unconquerable and weeks can pass without progress.

This paper is about the successful abandonment of such an episode of well control, in deepwater (i.e. greater than 300 m water depth), that was initially suspended with a closed-in subsea BOP. The BOP held in place a sheared 5-in. drillpipe that had been intermittently blowing dry gas and formation cuttings to the rig floor for 20 days.

The objective of the well-recovery operations was to re-enter the well and properly abandon it without creating another uncontrolled situation. All operations were to be conducted in compliance with HSE protocols.

It was paramount to have total control of the well at all times necessitating two BOP stacks. This contingency resulted in the suspension of a heavy load on the seabed, subject to excessive bending moments during bad weather. The well head arrangement was essential but the time loss caused by weather conditions was becoming intolerable. New and innovative plans made during the well-control operations cut 3 to 4 weeks of uninterrupted operation down to 5 days of operation. Cementing under pressure was the key abandoning solution. Several scenarios were drawn up for this eventuality and this paper elaborates on the decisions, choices, and solutions made during the final abandonment operation.
Measuring and Predicting Dynamic Sag
Authors: Murphy Robert , Jamison Dale , Hemphill Terry , Bell Stephen , Albrecht Carl
Published: July 2008

Weighting-material sag is a reoccurring problem with many oil-based drilling fluids. Attempts to correlate sag tendencies to various rheological properties commonly used to benchmark drilling fluids have had limited success in prevention and anticipation of sag problems in the field. This paper presents a new testing apparatus for dynamic and static settling-rate (sag) measurements, which has proved to provide a better understanding of the sag phenomena and a better means to characterize fluid performance. This apparatus greatly expands the precision of sag measurements over previous techniques and allows testing conditions similar to those experienced downhole. Good correlation has been found between settling-rate measurements and performance of drilling fluids in the field.
Universal Process for Benchmarking Drilling Fluid Performance
Authors: Zamora Mario , McGlaughlin Judith
Published: July 2008

A process has been developed to evaluate drilling fluid cost performance for a wide range of planning, intervention, and quality improvement activities. Meant to be universally applicable, the innovative process permits comparisons between similar and dissimilar wells drilled in the same or different global regions. It also can be used to contrast drilling fluid cost performance with operator-driven quality indicators to classify wells for front-end loading requirements for planning and to monitor actual-vs.-planned performance during drilling.

Methods normally used for drilling performance are not well-suited for benchmarking drilling-fluid performance. The approach introduced in this paper is based on a simple ratio that compares mud cost of a well to a corresponding technical limit. The technical-limit relationship, which uses a profile index to characterize well complexity, was derived empirically from a large internal database representing a wide assortment of well types, drilling conditions, and locations.

This paper describes the development and implementation of this process. Several case studies are presented to demonstrate specific applications. Although the process was developed strictly for internal use, full implementation details are provided to encourage its use by others in the industry involved with service-quality initiatives.
Rapid Planning and Execution of the First Multilateral Well in the Gulf of Thailand: Results and Lessons Learned
Authors: Upchurch Eric R. , Dooley Paul A. , Hall Kenneth H. , Laohaburanakit Songklod , Maroongroge Vichai , McKee L. Douglas , Nucharoen Panaratn , Wagner Michael R.
Published: July 2008

In early 2006, Chevron International E&P drilled and completed the first multilateral well in the Gulf of Thailand. Routine development drilling in the Kaphong field of the Pattani basin unexpectedly discovered two production horizons that possessed reservoir characteristics and sufficient oil reserves to make each a viable horizontal-well candidate. At the time, however, only a single drilling slot was available on the platform; thus, dictating that only one wellbore could be drilled to tap both reservoirs. Further complicating the problem was that the drilling rig that discovered the horizons would be moving to a new platform 5 weeks after it was understood by reservoir engineers, geologists, and geophysicists that multiple horizontal-well candidates existed.

This paper chronicles the rapid processes that took place to evaluate, plan, and execute the first multilateral well in the Gulf of Thailand. More importantly, this paper captures the unintended consequences (both good and bad) that came with executing this project so quickly. This includes an analysis of how decision making, project planning, and ultimate execution where affected by the short time window available. From this, we discuss lessons learned that may be universally applicable when rapidly expanding the use of technology in a remote region of the world (regardless of how small that expansion is).
Connection Performance Evaluation for Casing-Drilling Application
Authors: Lu Qing , Hannahs Dan , Wu Jiang , Langford Steve
Published: July 2008

With the evolution of casing-drilling technology, connections are subjected to increasingly stringent well conditions. These conditions include higher pressures, higher temperatures, and higher mechanical loads for longer drilling periods. As a result, the performance of the connector under these conditions is of increasing concern. Most recent casing connection evaluation test programs are based on International Standards Organization (ISO) 13679 (2002) requirements. However, API RP7 (1998) is the dominant testing program for drill stem applications. Because casing-drilling applications combine drilling and casing concerns, a new test protocol is required to adequately characterize connection performance (Hegler et al. 2004).

A better understanding of how connection tolerances impact connection performance under combinations of static and dynamic loading aids in connector selection and allows the technology to be used in broader casing-drilling applications. As part of the proposed test program, the static and dynamic connector performances are evaluated individually to benchmark the design. Based on these evaluations, additional testing was conducted to determine the connector static capacity after dynamic loading. This testing demonstrates the connector performance when used in casing-drilling applications.

This proposed testing protocol can be used to better define connector performance limits when used in casing-drilling applications leading to increased operational safety and lower overall risks. This paper includes results, observations, and conclusions from a subject test conducted in accordance with the proposed testing protocol on a 9-5/8-inch 53.50-ppf P-110 casing-drilling connector.
Correlations and Analysis of Cuttings Transport With Aerated Fluids in Deviated Wells
Authors: Avila R. , Pereira E. , Miska S. , Takach N. , Saasen A.
Published: July 2008

A study of cuttings transport at intermediate inclinations using aerated fluid, to determine the amount of solids that exist in the wellbore and minimum flow requirements for "clean-hole" condition, is presented. The experimental program included more than 300 tests, performed with a large-scale facility [100-ft-long flow loop with 8-in. outer diameter (OD) casing and 4.5-in.-OD drillpipe]. The angles of test section inclination were 30°, 45°, and 60° from vertical. Four pipe-rotational speeds (0, 40, 80, and 110 rpm) were used for different liquid-and gas-flow-rate combinations. New correlations were found to estimate the required critical-gas-flow rates for hole cleaning at specified liquid-flow rate and drillpipe-rotation combinations, and to predict volumetric cuttings concentration as a function of air and water flow rate, drillpipe-rotational speed, and inclination angle.
Patterns of Regional Yield Stability in Association with Regional Environmental Characteristics
Authors: Williams Carol L. , Liebman Matt , Edwards Jode W. , James David E. , Singer Jeremy W. , Arritt Ray , Herzmann Daryl
Published: July 2008

Regional‐level recurring spatial patterns of yield variability are important for commercial activities, strategic agricultural planning, and public policy, but little is known about the factors contributing to their formation. An important step to improve our understanding is recognizing regional spatial patterns of yield variability in association with regional environmental characteristics. We examined the spatial distribution of county‐level mean yields and CVs of mean yields of four functionally different crops—corn (Zea mays L.), soybean [Glycine max (L.) Merr.], alfalfa (Medicago sativa), and oat (Avena sativa L.)—in Iowa using Moran's Index of spatial autocorrelation. Patterns of association with 12 county‐level climatic, edaphic, and topographic environmental characteristics were examined using partial least squares regression. Two distinct geographic provinces of yield stability were identified: one in the northern two‐thirds of the state characterized by high mean yields and high yield constancy, and one in the southern third of the state characterized by low mean yields and low yield constancy. Among eight partial least squares regression models, which explained 50 to 81% of variation of mean yields and yield CVs, mean organic matter and mean depth to seasonally high water table had greatest relative importance to mean yields of grass crops and legume crops, respectively. Among the CV models, variables describing water availability were of greatest relative importance, with less distinct differences between grass and legume crops. Partial least squares regression is a potentially powerful tool for understanding regional yield variability.
Evaluation and Modeling of Physical and Physiological Damage to Wheat Seeds under Successive Impact Loadings: Mathematical and Neural Networks Modeling
Authors: Khazaei Javad , Shahbazi Feizollah , Massah Jafar , Nikravesh Mehdi , Kianmehr Mohammad H.
Published: July 2008

Threshing wheat (Triticum aestivum L.) at high speeds is the main reason behind abnormal seedlings and vigor reduction of the seeds. This problem is expected to be severe in head‐stripper combines with successive impact loadings of stripping and threshing units. The aim of this study was to simulate the effects of impact velocities (IV), number of impact loadings (NL), and seed moisture content (MC) on percentage of physical damage (PPD) and percentage of loss in germination (PLG) to wheat seeds. Modeling the correlation between dependent and independent variables was performed using mathematical and artificial neural networks (ANN). The result showed that all the three independent variables significantly influenced PPD and PLG (P = 0.01). Increasing the IV from 5 to 30 m s−1 caused an increase in PPD and PLG from 0.17 to 35.8% and from 0.37 to 19.9%, respectively. It was found that the seeds with higher MC could better withstand physical and physiological damage than those with lower MC. With an increase in NL from 1 to 3 times, the mean values of PPD and PLG were increased by 2.9 and 2.6 times, respectively. An ANN model with two hidden layers, trained with a back‐propagation algorithm, successfully learned the relationship between the input and output variables. In comparison with regression models, ANN performed better when predicting PPD and PLG to wheat seeds.
Anthracnose Severity on Annual Bluegrass Influenced by Nitrogen Fertilization, Growth Regulators, and Verticutting
Authors: Inguagiato John C. , Murphy James A. , Clarke Bruce B.
Published: July 2008

Frequency and severity of anthracnose epiphytotics, caused by Colletotrichum cereale Manns Manns sensu lato Crouch, Clarke, and Hillman, on annual bluegrass (ABG) [Poa annua L. f. reptans (Hauskins) T. Koyama] putting greens have increased over the past decade. This 3‐yr field study evaluated the impact of N fertilization (4.9 kg ha−1 every 7 or 28 d), mefluidide (ME; 0 and 0.106 kg a.i. ha−1 yr−1) {N‐[2,4‐dimethyl‐5‐[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide}, trinexapac‐ethyl (TE; 0 and 0.050 kg a.i. ha−1 every 14 d) [4‐(cyclopropyl‐α‐hydroxy‐methylene)‐3,5‐dioxocyclohexanecarboxylic acid ethylester], verticutting (VC; 0‐ and 3‐mm depth every 14 d), and interactions of these factors on anthracnose of ABG mowed at 3.2 mm. Nitrogen fertilization frequency had the greatest influence on disease throughout the study; N applied at 4.9 kg ha−1 every 7 d reduced damage 5 to 24% compared to a 28‐d interval. The plant growth regulators, ME and TE, frequently interacted during the last 2 yr of the study; sequential application of ME and TE reduced disease 6 to 14% compared to plots that only received one of these plant growth regulators. At advanced stages of disease, the combination of 7‐d N fertilization and ME and TE application had the greatest disease reduction. Verticutting had little effect on anthracnose severity.
Comparison of Catalysts for Direct Transesterification of Fatty Acids in Freeze‐Dried Forage Samples
Authors: Weston T. R. , Derner J. D. , Murrieta C. M. , Rule D. C. , Hess B. W.
Published: July 2008

Preparation of fatty acid methyl esters from forages comparing methanolic boron‐trifluoride (BF3) to methanolic hydrochloric acid (HCl) as a catalyst in single‐step direct transesterification has not been reported. Our objective was to compare 1.09 M methanolic HCl to 1.03 M (7%) methanolic BF3 as catalysts for direct transesterification of fatty acids in freeze‐dried forage samples. Thin‐layer chromatographic analysis revealed complete conversion of total lipid extracts to fatty acid methyl esters using both catalysts. Additionally, gas–liquid chromatography analysis confirmed similar (P = 0.95) total fatty acid concentrations for both catalysts. Regression analysis indicated that similar values for total concentration would be obtained (P < 0.0001; r2 = 0.96; slope = 0.98 ± 0.03) between the two catalysts. Concentrations of most individual fatty acids were similar (P = 0.17–0.99) for both catalysts. Summed weight percentages of identified fatty acids, as well as sum of unidentified peaks, were not affected (P = 0.27) by catalyst (91.8 and 8.7% vs. 90.8 and 9.2% for HCl and BF3, respectively). We conclude that 1.09 M methanolic HCl is an appropriate substitute for 1.03 M methanolic BF3 for preparation of fatty acid methyl esters from freeze‐dried forage samples. This result is of interest because HCL is both less costly and less caustic than BF3
Mass Selection for Small Seed Size in Natto Soybean Populations and the Resulting Effect on Seed Yield
Authors: Cober Elroy R. , Voldeng Harvey D.
Published: July 2008

Natto soybean [Glycine max (L.) Merr.] cultivars are typically small seeded and seed yield is generally lower than that of oilseed cultivars. We investigated the effects of mass selection for small seed size on seed yield. Two sets of populations were developed, from crosses of natto and larger‐seeded parents, using mass selection; nine tested in three site‐years in 2003 and 2004, and four tested from 2002 to 2004. Populations were advanced with mass selection for seed size applied to F3 and F4 seeds using either no. 14 or 15 round‐hole sieves. F4:5 recombinant inbred lines (RILs) from AC Colibri/OT91‐3, unselected for seed size, were evaluated from 2002 to 2004. Selection for small seed reduced seed weight but did not affect yield or days to maturity when comparing two sieve sizes. The seed yield of natto selections remained at about 80% of the oilseed check cultivars in this study. In nine populations, among progenies resulting from mass‐selection for seed size, random selections were significantly higher yielding and later maturing but did not differ in seed weight compared to visually selected lines. In four populations segregating for leaflet shape, mass selection for small seed size resulted in more narrow‐leaflet lines. Selection for narrow leaflets may aid in reducing seed size in some populations. The seed size distribution of the RILs suggests that selection for small seed size may cause a bottleneck in mass selected populations and result in small effective population sizes.
Yield Performance and Stability Evaluation of Peanut Breeding Lines with the CSM‐CROPGRO‐Peanut Model
Authors: Suriharn B. , Patanothai A. , Pannangpetch K. , Jogloy S. , Hoogenboom G.
Published: July 2008

Multienvironment trials of crop breeding lines consume many resources. Crop models have a potential to assist in this process. The goal of this study was to evaluate the potential of the CSM‐CROPGRO‐Peanut model in assisting with yield performance and stability evaluation of peanut (Arachis hypogaea L.) breeding lines. Seventeen peanut lines were tested in 11 environments in Thailand during both the rainy and the dry seasons of 2002 to 2004. Yields of these lines were also simulated with the CSM‐CROPGRO‐Peanut model for the same 11 test sites. The cultivar coefficients of the peanut lines used for model simulation were derived from a separate experiment conducted in two seasons and were evaluated against an independent data set from another experiment. Yield performance and stability of the peanut lines were evaluated on the basis of observed and simulated data using the genotype and genotype × environment interaction biplot method. The results showed that the model predicted the relative performances and yield stability for pod yield of the test peanut lines for the 11 actual test sites reasonably well. Out of the nine highest yielding lines, that is, the upper 52%, identified by observed data, six were identified by model simulation. Similarly, out of the nine stable lines identified by observed data, six were common with those identified by simulated data. We conclude that the CSM‐CROPGRO‐Peanut model could be used in assisting yield performance and stability evaluation of peanut breeding lines.
Quantitative Trait Loci Analysis of Allelopathy in Rice
Authors: Jensen L. B. , Courtois B. , Olofsdotter M.
Published: July 2008

The allelopathic potential of rice (Oryza sativa L.) against Echinochloa crus‐galli (L.) Beauv. was investigated under both laboratory and greenhouse conditions. A population of 150 recombinant inbred lines (RILs) was derived through single‐seed descent from a cross between the indica cultivar AC1423, known to have a strong allelopathic potential, and the aus cultivar Aus196, with low allelopathic potential. The RILs together with the parents were first phenotyped using the laboratory assay known as the relay seeding technique. The screening showed that with regards to allelopathic potential the population phenotype was normally distributed. Two quantitative trait loci (QTLs) were located on chromosomes 4 and 7, explaining 20% of the phenotypic variation. A second relay seeding experiment was set up, this time including charcoal in the perlite. This screening showed that the allelopathic rice varieties did not have any effect on the weed species when grown with charcoal, the charcoal reversing the effect of any potential allelochemicals exuded from the rice roots. The second phenotypic experiment was conducted under greenhouse conditions in pots. Thirteen QTLs were detected for four different allelopathic measurements, located on seven chromosomes, and individually explaining between 5 and 10% of the phenotypic variation. Some QTLs from both experiments located to the same genomic regions. The results show that breeding to increase rice allelopathic potential is possible.