bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling of current—voltage characteristics for double‐gate a‐IGZO TFTs and its application to AMLCDs
Authors: Baek Gwanghyeon , Kanicki Jerzy
Published: April 2012

Abstract— The equations for the transfer characteristics, subthreshold swing, and saturation voltage of double‐gate (DG) a‐IGZO TFTs, when the top‐ and bottom‐gate electrodes are connected together (synchronized), were developed. From these equations, it is found thatsynchronized DG a‐IGZO TFTs can be considered as conventional TFTs with a modified gate capacitance and threshold voltage. The developed models were compared with the top or bottom gate only bias conditions. The validity of the models is discussed by using the extracted TFT parameters for DG coplanar homojunction TFTs. Lastly, the new pixel circuit and layout based on a synchronized DG a‐IGZO TFT is introduced.
LED‐backlit computer screens influence our biological clock and keep us more awake
Authors: Bues Matthias , Pross Achim , Stefani Oliver , Frey Silvia , Anders Doreen , Späti Jakub , Wirz‐Justice Anna , Mager Ralph , Cajochen Christian
Published: April 2012

Abstract—In commodity LC flat‐panel displays, the traditional CCFL backlight is being replaced more and more by LEDs. The typical spectrum of LED‐lit displays shows a significantly higher amount of blue light in the range around 464 nm. Blue light in this wavelength area suppresses the melatonin level in humans and thus effects the biological clock. Our hypothesis was that the amount of blue light reaching the human eye from a LED‐backlit display is sufficient to have a significant effect on the biological clock. The results of clinical user studies comparing the effects of LED‐vs. CCFL‐backlit displays on humans, resulting from the emitted amount of 464‐nm light, will be presented. It was found that the LED‐backlit display causes significant suppression of melatonin, which effects the biological clock of the test persons, indicating the necessity for displays with a controllable 464‐nm emission. A technical concept for a display with such functionality will be presented.
Laser + LCOS projection‐technology revolution
Authors: Guttag Karl M. , Hurley Shawn
Published: April 2012

Abstract— The advent of affordable direct‐diode lasers changes all the rules for optical designs and the associated technologies that generate the images from laser light. These new lasers are forseen as driving fundamental changes in the size, power consumption, cost, resolution, and even the uses for pico‐projectors. This paper discusses these topics from the perspective of laser‐light‐illuminated LCOS microdisplays.
Transient dynamics and the destabilizing effects of prey heterogeneity
Authors: Steiner Christopher F. , Klausmeier Christopher A. , Litchman Elena
Published: April 2012

The presence of prey heterogeneity and weakly interacting prey species is frequently viewed as a stabilizer of predator–prey dynamics, countering the destabilizing effects of enrichment and reducing the amplitude of population cycles. However, prior model explorations have largely focused on long‐term, dynamic attractors rather than transient dynamics. Recent theoretical work shows that the presence of prey that are defended from predation can have strongly divergent effects on dynamics depending on time scale: prey heterogeneity can counteract the destabilizing effects of enrichment on predator–prey dynamics at long time scales but strongly destabilize systems during transient phases by creating long periods of low predator/prey abundance and increasing extinction probability (an effect that is amplified with increasing enrichment). We tested these general predictions using a planktonic system composed of a zooplankton predator and multiple algal prey. We first parameterized a model of our system to generate predictions and tested these experimentally. Our results qualitatively supported several model predictions. During transient phases, presence of defended algal prey increased predator extinctions at low and high enrichment levels compared to systems with only a single edible prey. This destabilizing effect was moderated at higher dilution rates, as predicted by our model. When examining dynamics beyond initial oscillations, presence of the defended prey increased predator–prey temporal variability at high nutrient enrichment but had no effect at low nutrient levels. Our results highlight the importance of considering transient dynamics when assessing the role of stabilizing factors on the dynamics of food webs.
Experimental manipulation of seed shadows of an Afrotropical tree determines drivers of recruitment
Authors: Poulsen John R. , Clark Connie J. , Bolker Benjamin M.
Published: April 2012

The loss of animals in tropical forests may alter seed dispersal patterns and reduce seedling recruitment of tree species, but direct experimental evidence is scarce. We manipulated dispersal patterns of Manilkara mabokeensis, a monkey‐dispersed tree, to assess the extent to which spatial distributions of seeds drive seedling recruitment. Based on the natural seed shadow, we created seed distributions with seeds deposited under the canopy (“no dispersal”), with declining density from the tree (“natural dispersal”), and at uniform densities (“good dispersal”). These distributions mimicked dispersal patterns that could occur with the extirpation of monkeys, low levels of hunting, and high rates of seed dispersal. We monitored seedling emergence and survival for 18 months and recorded the number of leaves and damage to leaves. “Good dispersal” increased seedling survival by 26%, and “no dispersal” decreased survival by 78%, relative to “natural dispersal.” Using a mixed‐effects survival model, we decoupled the distance and density components of the seed shadow: seedling survival depended on the seed density, but not on the distance from the tree. Although community seedling diversity tended to decrease with longer dispersal distances, we found no conclusive evidence that patterns of seed dispersal influence the diversity of the seedling community. Local seed dispersal does affect seedling recruitment and survival, with better dispersal resulting in higher seedling recruitment; hence the loss of dispersal services that comes with the reduction or extirpation of seed dispersers will decrease regeneration of some tree species.
There are many ways to be a mutualist: Endophytic fungus reduces plant survival but increases population growth
Authors: Rudgers Jennifer A. , Miller Tom E. X. , Ziegler Shaun M. , Craven Kelly D.
Published: April 2012

One of the challenges to quantifying the costs and benefits of symbiosis is that symbionts can influence different components of host fitness. To improve understanding of the ecology of inherited symbionts, we developed general theory for a perennial host–hereditary symbiont interaction, in which symbionts can have independent and potentially opposing effects on host regeneration and survival. The model showed that negative effects on one component of fitness may be outweighed by positive effects on another, leading to a net positive impact of symbiosis on population growth. Model predictions depended on the availability of suitable patches, which influenced the relative contributions of survival vs. regeneration to host fitness. We then used experimental symbiont removal to quantify effects of a hereditary, fungal endophyte on a grass host. Endophyte presence strongly reduced host survival but increased regeneration. Application of the model revealed that negative effects on plant survival were overwhelmed by beneficial effects on regeneration, resulting in stable endophyte persistence at 100% frequency, consistent with field observations. Our work demonstrates the utility of a demographic perspective for predicting the dynamics of symbioses and supports the hypothesis that symbionts function as mutualists when host and symbiont fitness are coupled through vertical transmission.
A rediscovered treasure: mycorrhizal intensity database for 3000 vascular plant species across the former Soviet Union
Authors: Akhmetzhanova Asem A. , Soudzilovskaia Nadejda A. , Onipchenko Vladimir G. , Cornwell Will K. , Agafonov Vladimir A. , Selivanov Ivan A. , Cornelissen Johannes H. C.
Published: April 2012

The symbiosis between vascular plants and mycorrhizal fungi is paramount for carbon and nutrient cycling in most of the world's ecosystems. Most vascular plant species are associated with mycorrhizal fungal partners, and the association is essential for the carbon and nutrition economies of both partners. However, despite its clear importance, data on this symbiosis are lacking: for most vascular plant species, mycorrhizal type is unknown. Very rarely is there data on the levels of mycorrhizal infection intensity in multiple habitats.

We translated and digitized a huge data set on vascular plant mycorrhizal intensity throughout the former Soviet Union, previously available only as a hard copy appendix of the doctoral thesis of Ivan A. Selivanov published in Russian in 1976 and not accessible to the international research community. We updated the taxonomic plant nomenclature to the International Plant Name Index and adjusted mycorrhizal and ecological terminology according to the modern international literature.

The database contains 7445 records on mycorrhizal infection type and intensity of 2970 plant species from 155 families, in 154 sites, situated across the former Soviet Union (mostly on the territory of the current Russia, Ukraine, and Kazakhstan), comprising together extensive geological, topographic, and climatic gradients. The data set includes percentage infection for each species–site combination for arbuscular, ericoid, arbutoid, endo‐mycorrhizal, dark septate, orchid‐ and ecto‐mycorrhizal fungi. Each record has a detailed description of geography. For many records, soils and host plant community are described. Most of the sites are natural; 10 sites are situated in botanical gardens. For 1291 species the intensity of mycorrhizal infection is quantified in multiple plant communities (2–57). The remaining species are described at single sites.

Selivanov developed his own methods for quantifying mycorrhizal infection intensity. These methods are comparable, but not identical to, the methodology commonly used today. Based on our own sampling of 99 plant species collected in two distant sites (Caucasus [Russia] and Abisko [Sweden]), we provide a simple equation for data conversion between the two methods.

The availability of this database will help to provide answers to important questions concerning biogeochemical cycling, climate change impacts, and co‐evolution of plants and fungi.

The complete data sets corresponding to abstracts published in the Data Papers section of the journal are published electronically in Ecological Archives at 〈http://esapubs.org/archive〉. (The accession number for each Data Paper is given directly beneath the title.)
Methodology and performance of a rainfall manipulation experiment in a piñon–juniper woodland
Authors: Pangle Robert E. , Hill Judson P. , Plaut Jennifer A. , Yepez Enrico A. , Elliot James R. , Gehres Nathan , McDowell Nate G. , Pockman William T.
Published: April 2012

Climate models predict that water limited regions around the world will become drier and warmer in the near future, including southwestern North America. We developed a large‐scale experimental system that allows testing of stand level impacts of precipitation changes. Four treatments were applied to 1600 m2 plots (40 m × 40 m), each with three replicates in a piñon pine (Pinus edulis) and juniper (Juniper monosperma) ecosystem. These species have extensive root systems, requiring large‐scale manipulation to effectively alter soil water availability. Treatments consisted of: (1) irrigation plots that receive supplemental water additions, (2) drought plots that receive 55% of ambient rainfall, (3) cover‐control plots that receive ambient precipitation, but allow determination of treatment infrastructure artifacts, and (4) ambient control plots. Our drought structures effectively reduced soil water potential and volumetric water content compared to the ambient, cover‐control, and water addition plots. Drought and cover‐control plots experienced an average increase in maximum soil and ground‐level air temperature of 1–4°C during the growing season compared to ambient plots, and concurrent short‐term diurnal increases in maximum air temperature were also observed directly above and below plastic structures. Our drought and irrigation treatments significantly influenced tree predawn water potential and canopy transpiration, with drought treatment trees exhibiting significant decreases in physiological function compared to ambient and irrigated trees. Supplemental irrigation resulted in a significant increase in both plant water potential and canopy transpiration compared to trees in the other treatments. This experimental design allows manipulation of plant water stress at the tree/stand scale, permits a wide range of drought conditions, and provides prolonged drought conditions comparable to historical droughts in the past—drought events for which wide‐spread mortality in both these species was observed.
Growth Factor‐Mediated Sinus Augmentation Grafting With Recombinant Human Platelet‐Derived Growth Factor‐BB (rhPDGF‐BB): Two Case Reports
Authors: Scheyer E. Todd , McGuire Michael K.
Published: April 2012

Introduction: In the following two case reports, growth factor‐mediated sinus augmentation surgery is used to treat significant posterior maxillary alveolar bone deficiency. At initial examination, preexisting subsinus alveolar bone height was ≤3 mm. A composite graft of anorganic bovine bone mineral (ABBM) + mineralized bone allograft was combined with recombinant human platelet‐derived growth factor‐BB (rhPDGF‐BB) for augmentation grafting via a traditional maxillary lateral wall osteotomy approach to the sinus. In both cases, early implant placement and loading following sinus grafting, as well as long‐term clinical follow‐up, document potential benefits of growth factor‐mediated bone regenerative sinus augmentation procedures. The significantly abbreviated durations seen in these two cases between sinus augmentation grafting and implant placement and prosthetic restoration, to the best of our knowledge, have not been previously reported in the literature.

Case Presentations: Two adult males presented with severe posterior maxillary alveolar bone atrophy, with a maximum subsinus bone height of 3 mm in patient #1 and <1 mm in patient #2. For each patient, a 50:50 particulate composite graft of ABBM and mineralized allograft was hydrated with 1 mL of 0.3 mg/mL rhPDGF‐BB. Four and one‐half (4.5) and 3.5 months following grafting in patient #1 and #2, respectively, implants were placed and core biopsy specimens obtained. Histologic examination of osteotomy cores demonstrated significant amounts of vital bone for each patient. Definitive implant‐supported restorations in full occlusion were placed 8.5 and 7.5 months following sinus grafting for patient #1 and #2, respectively. Three (3) and 2.4 years following implant placement, all implants were well integrated, with no evidence of radiolucency at the implant‐to‐bone interface.

Conclusion: The addition of tissue‐engineered proteins, i.e., rhPDGF‐BB, to sinus augmentation protocols may allow earlier implant placement secondary to accelerated bone formation following grafting in the severely pneumatized sinus and may provide for increased long‐term positive clinical outcomes.
Palatal Tissue Enlargement After Subepithelial Connective Tissue Graft Harvest Associated With Anabolic Steroid Abuse
Authors: Soolari Ahmad , Soolari Ehsan , Shumaker Nicholas D.
Published: April 2012

Introduction: Healing complications associated with androgenic anabolic steroid (AAS) abuse have received minimal attention in the periodontal literature. This case report describes an adverse healing event after palatal subepithelial connective tissue graft (SECTG) harvest associated with AAS abuse.

Case Presentation: A 35‐year‐old white male was treated with an SECTG procedure to address gingival recession on the facial aspect of teeth #24 and #25. Donor tissue was harvested from the left hard palate via a single incision technique. The procedure was completed without complication. One week postoperatively, the patient presented with a large asymptomatic overgrowth of tissue from the palatal harvest site. Over the following 5 weeks of continued observation, the lesion demonstrated progressive, spontaneous resolution. Investigation of possible etiology revealed the subject was a recreational bodybuilder with admitted AAS abuse.

Conclusions: Post‐surgical healing can be influenced by AAS abuse. Alterations in connective tissue metabolism and fibroblast activity are known sequelae of AAS abuse; however, patients may be reluctant to admit to steroid abuse during the presurgical interview. Surgeons should suspect the possibility of AAS abuse when postoperative complications present in a patient of muscular body type.
Cryosurgical Treatment of Gingival Melanin Pigmentation — A 30‐Month Follow‐Up Case Report
Authors: Ahmed Shaeesta Khaleel , George Joann Pauline , Prabhuji M. L. V. , Lazarus Flemingson
Published: April 2012

Introduction: Cryosurgery is a branch of therapeutics that makes use of local freezing for the controlled destruction or removal of living tissues. Cryosurgery has been tried with satisfactory results for gingival depigmentation. However, documented evidence in the literature is extremely limited. The present case report describes the successful management of excessive gingival pigmentation by cryosurgery. The patient underwent follow‐up for 30 months.

Case Presentation: A 21‐year‐old South Indian dark‐skinned female presented with dark brown to black gingival melanin pigmentation. The darkly pigmented gingiva had been present since birth. Cryosurgery using nitrous oxide and gas expansion cryoprobe cooled to −70°C was used for the depigmentation. The depigmentation was performed from maxillary right cuspid to maxillary left cuspid in a single appointment. The patient reported no adverse effects and no repigmentation of the treated areas for a period of 30 months.

Conclusions: Cryosurgery is an easy procedure, with lack of bleeding and scar formation. The esthetic outcome may be maintained for 30 months as shown in the present case. Cryosurgery can be considered a desirable treatment option for gingival depigmentation.
The Use of a Xenogeneic Collagen Matrix as an Interpositional Soft‐Tissue Graft to Enhance Peri‐Implant Soft‐Tissue Outcomes: A Clinical Case Report and Histologic Analysis
Authors: Mandelaris George A. , Lu Mei , Rosenfeld Alan L.
Published: April 2012

Introduction: Keratinized and dense peri‐implant soft tissue around implants has been associated with better tissue health, less bone loss, and improved esthetics. The purpose of this case report is to evaluate a new, xenogeneic collagen matrix (CM) as an interpositional soft‐tissue graft to enhance peri‐implant soft‐tissue thickness. To our knowledge, this is the first such case report to include soft‐tissue biopsies and histologic analysis.

Case Presentation: After extraction and bone grafting of a mandibular left first molar, the patient received a dental implant, and CM was used as an interpositional soft‐tissue graft. Clinical healing was uneventful, and the impression of enhanced soft‐tissue volume/thickness was observed. At 10 weeks, biopsies were taken from the operative site and from a contralateral, non‐operated site. Histologic assessment of the operative site demonstrated normal squamous epithelium and lamina propria. Tissue growing into the residual CM also appeared normal, with no inflammatory cells seen in the graft area. Vascular blood vessels were observed growing into the matrix. Control and test sites were comparable.

Conclusions: This case report and the first examination of a human biopsy around a dental implant demonstrate that CM holds promise as an effective, time‐efficient, and reduced morbidity alternative to autogenous graft harvest for the promotion of peri‐implant soft‐tissue thickness. CM was easy to handle, place, and suture, and histologic analysis indicated a benign tissue response resulting in an organized and attached connective tissue similar to native, undisturbed periodontal tissue.
Conservative Treatment of Localized Juvenile Spongiotic Gingival Hyperplasia
Authors: MacNeill Simon R. , Rokos James W. , Umaki Michael R. , Satheesh Keerthana M. , Cobb Charles M.
Published: April 2012

Introduction: Localized juvenile spongiotic gingival hyperplasia (LJSGH) is a recently described uncommon and distinctive form of inflammatory hyperplasia. Treatment of this condition has varied from surgical excision to no treatment followed by spontaneous remission. This case report demonstrates successful management of the lesion using a conservative treatment approach.

Case Presentation: A 14‐year‐old male with negative medical and dental histories presented with LJSGH. The vivid red lesions involved the papillary and marginal gingiva of all maxillary anterior teeth. Initially, the lesion developed as a single red patch‐like area involving the maxillary left cuspid. Subsequently, the lesion displayed a linear pattern of spread to involve successively more teeth in the anterior sextant. Biopsy revealed hyperplastic elongated epithelial rete pegs, atrophy of the overlying stratified squamous epithelium with mild spongiosis, neutrophilic exocytosis, and a highly vascular connective tissue with a dominant infiltrate of chronic inflammatory cells. The lesion responded to treatment consisting of a mild surface cauterization followed by topical application of a 0.05% clobetasol ointment four times per day for a period of 4 weeks.

Conclusion: This case report demonstrates that LJSGH can be successfully managed by conservative therapy, thereby avoiding potential gingival margin defects that may result from a surgical ablation of the lesion.
Non‐Plaque‐Induced Gingivitis Associated With Isotretinoin: A Case Report
Authors: Mahajan Ajay , Bharadwaj Ashu , Mahajan Poonam
Published: April 2012

Introduction: Isotretinoin (13‐cis‐retinoic acid), a synthetic vitamin A derivative, is used to treat a wide variety of dermatologic conditions, including severe acne. Although isotretinoin has revolutionized the management of acne vulgaris, concerns continue regarding the adverse effect profile of isotretinoin. Mucocutaneous reaction is the most commonly observed adverse side effect of isotretinoin use, but the involvement of gingival mucosa has rarely been reported. To our knowledge, this is the first‐ever case report of gingivitis associated with isotretinoin.

Case Presentation: A 19‐year‐old female was referred to the Department of Periodontics, Himachal Pradesh Government Dental College and Hospital, Shimla, India, for the treatment of persistent severe gingivitis. The history of the patient revealed that she had been on 10 mg/day isotretinoin regimen for the treatment of nodular facial acne for 6 months. In the absence of an obvious cause, the condition was diagnosed as isotretinoin‐associated gingivitis. After consultation with the dermatologist, the drug was stopped and the patient responded favorably to periodontal treatment.

Conclusion: Non‐plaque‐induced, isotretinoin‐associated gingivitis should always be suspected in a patient who is taking isotretinoin and has persistent gingivitis that does not respond to periodontal treatment.
Successful Gingival Depigmentation With Laser‐Patterned Microcoagulation: A Case Report
Authors: Allen Edward P. , Gladkova Natalia D. , Fomina Yulia V. , Karabut Maria M. , Kiseleva Elena B. , Feldchtein Felix I. , Altshuler Gregory B.
Published: April 2012

Introduction: Current methods for gingival depigmentation, including mechanical surgery, cryosurgery, laser treatments, and radiosurgery, create significant patient discomfort and risk of complications, thereby reducing attractiveness of the depigmentation procedure for many patients. To our knowledge, this case report presents a first‐time application of a new technology, laser‐patterned microcoagulation (LPM) based on the concept of fractional laser photothermolysis that was successfully applied in dermatology and ophthalmology.

Case Presentation: One patient was treated for local hyperpigmentation of the labial attached gingiva in the maxillary anterior area. A diode laser with wavelength 980 nm and power 20 W was used to create microcoagulation columns with a 30% area filling factor. Two treatments were performed, 2 weeks apart, without anesthesia. The patient was followed for 5 months. The discomfort during the procedure was tolerable without anesthesia. Healing was uneventful and visually completed with significant reduction of pigmentation at 2 weeks after treatment. Complete visual depigmentation was observed at both 2 weeks and 2 months after the second treatment.

Conclusions: To our knowledge, this is the first clinical case of hyperpigmentation treatment using LPM, demonstrating feasibility of a new, minimally invasive and effective method of localized gingival hyperpigmentation removal. The patient discomfort is significantly less than that reported for other methods for depigmentation.
Primary Non‐Hodgkin Lymphoma of Palatal Gingiva
Authors: Sharma Rajinder K. , Yadav Vikender S. , Kataria Sant P. , Tewari Shikha , Narula Satish C.
Published: April 2012

Introduction: Non‐Hodgkin lymphomas (NHLs) are a heterogeneous group of lymphoproliferative malignancies that can disseminate to organs and tissues that do not ordinarily contain lymphoid cells (extranodal sites). Primary extranodal NHL of the oral cavity is rare, and gingiva is one of the rarest intraoral sites involved. The majority of oral NHLs reported are of diffuse large B‐cell type. Such lymphomas are more prevalent in immunocompromised patients. Because of their malignant nature, early recognition, diagnosis, and treatment are essential for a patient's survival. To the best of our knowledge, this report presents the first case of diffuse mixed small and large B‐cell lymphoma involving the gingiva in a non‐immunocompromised patient.

Case Presentation: A female patient presented with a growth located on the palatal aspect of the right maxillary molar region involving marginal and interdental gingiva. Routine laboratory tests and clinical examination were within normal limits. An incisional biopsy of the gingival tissue was evaluated using histologic techniques and immunohistochemistry. A diagnosis of extranodal diffuse mixed small and large B‐cell lymphoma was established. The patient underwent a complete workup to rule out other systemic lesions, thereby supporting the primary nature of the lesion.

Conclusion: Gingival overgrowth may rarely be the first manifestation of extranodal NHL. Only histopathological examination of the specimen with immunohistochemistry can ascertain a confirmed diagnosis of NHL. The present case report stresses the importance of routine biopsy examination for growth lesions of long duration when an infectious etiology has been ruled out, even if the lesions appear benign.
An Unusual Plasma Cell Gingivitis Case Related to Use of Herbal Toothpowder
Authors: Agarwal Sangita , Ajmera Neha , Chatterjee Anirban , Madaiah Hemalata
Published: April 2012

Introduction: Plasma cell gingivitis (PCG) is a rare benign condition of gingiva marked by dense infiltration of plasma cells into the subepithelial gingival tissue. Considered to be a true hypersensitivity reaction, it leads to edematous enlargement of gingiva extending up to the mucogingival junction. Identification and removal of the allergen leads to remission of the lesion. This case describes an unusual case of PCG.

Case Presentation: The patient did not respond well to conventional periodontal therapy. Discontinuation of herbal toothpowder with surgical periodontal therapy led to remission of gingival enlargement. Massive enlargement responded well to removal of allergen and surgical periodontal therapy. There was no evidence of recurrence at the 18 month follow‐up.

Conclusion: Clinicians should be aware of the adverse effects of herbal agents used in dentifrices, and caution should be exercised against excessive use of such products.
Use of Platelet‐Rich Plasma Combined With Hydroxyapatite in the Management of a Periodontal Endosseous Defect Associated With a Palato‐Radicular Groove: A Case Report
Authors: Guruprasad C.N. , Pradeep A.R. , Agarwal Esha
Published: April 2012

Introduction: Various root developmental anomalies, such as palato‐radicular groove, have been associated with worsening the periodontal condition. Platelet‐rich plasma (PRP), an autologous concentration of platelets, has been reported to significantly enhance bone and soft‐tissue healing and the combination of PRP and a hydroxyapatite (HA) osseous graft has been demonstrated to be efficacious in the treatment of periodontal endosseous defects. Here, we present a 1‐year follow‐up report of such a clinical case, treated by the combined use of PRP and HA osseous graft for periodontal regeneration and, finally, restorative therapy.

Case Presentation: A 36‐year‐old Indian female reported with pain in the upper maxillary incisor region. On clinical and radiologic examination, a deep 3‐wall periodontal endosseous defect was found mesial to the maxillary left lateral incisor that was etiologically associated with the presence of a palato‐radicular groove, leading to the development of a periapical lesion. Endodontic therapy, non‐surgical periodontal therapy, and surgical periodontal therapy with a mixture of PRP gel and HA were performed. One‐year examination showed uneventful healing and complete elimination of the periodontal pocket.

Conclusions: A palato‐radicular groove may serve as a pathway for the development of a periodontal endosseous defect and for pulpal involvement. The combination of PRP and HA may be efficacious in the treatment of such a periodontal endosseous defect. Additional research should be performed to evaluate the efficacy of PRP and HA in the treatment of periodontal endosseous defects.
Unusual Implant Failure and Concurrent Lung Infection
Authors: Deporter Douglas , Hutcheon Michael
Published: April 2012

Introduction: A patient with a history of treated periodontal disease with multiple tooth loss was seeking dental implant treatment.

Case Presentation: After aggressive sanative therapy and a single pocket‐reduction surgery, treatment proceeded with one mandibular implant, one immediate maxillary implant, and minor sinus grafting using the crestal approach. Both implants failed to integrate due to infections that appeared unrelated to known periodontal pathogens. Patient referral for additional medical investigation led to diagnosis of serious lung infections. Once the lung conditions were managed with antibiotics, implant retreatment was successful.

Conclusion: When dental implants fail, every attempt should be made to understand why and include further medical investigation where indicated.
Severe Localized Gingival Recession Developing During Pregnancy
Authors: Parashis Andreas O. , Tatakis Dimitris N.
Published: April 2012

Introduction: Gingival recession typically develops over a long period of time. Development or progression of gingival recession in a short time and in the absence of acute trauma is exceedingly rare. The aim of this case report is to present a case of severe gingival recession developing in a systemically healthy patient during the last trimester of a routine pregnancy.

Case Presentation: A 34‐year‐old woman, successfully treated 3 years earlier for a localized gingival recession on tooth #24, compliant with home care and maintenance visits, discontinued maintenance during pregnancy. A localized 2‐mm deep Miller Class I recession defect on tooth #26 was under follow‐up and had been stable during maintenance. The patient presented at 2‐months postpartum. She reported that she had noticed localized inflammation and progression of the recession on tooth #26 during the last gestational trimester; she denied any history of trauma. During examination, the recession on tooth #26 had progressed into a 6‐mm deep Miller Class II defect. The defect was treated with a connective tissue graft procedure. At 14 months after surgery, the clinical outcome remained satisfactory and stable.

Conclusions: Rapid and severe localized gingival recession can occur during routine pregnancy. In light of the evidence indicating safety of routine periodontal care during pregnancy, pregnant females should be encouraged to continue their maintenance periodontal care to minimize the potential of irreversible sequelae from pregnancy‐associated gingival inflammation.
Enamel Matrix Proteins and Periodontal Wound Healing and Regeneration
Authors: Sculean Anton , Alessandri Regina , Miron Richard , Salvi Giovanni E. , Bosshardt Dieter D.
Published: April 2012

Introduction: The goal of regenerative periodontal therapy is the reconstitution of lost periodontal structures (i.e., the new formation of root cementum, periodontal ligament, and alveolar bone). Results from preclinical and clinical research in the last decade have provided evidence on the biologic rationale and clinical applications of an enamel matrix derivative (EMD) protein in periodontal wound healing and regeneration.

Case Presentations and Literature Overview: This paper will provide an overview of the biologic rationale for using enamel matrix proteins (EMPs) in regenerative periodontal therapy. Based on the available preclinical and clinical evidence, the main clinical indications for using EMD in regenerative periodontal therapy will be discussed.

Conclusions: The available data provide evidence of the biologic rationale of EMPs to support periodontal wound healing and regeneration. The application of EMD in conjunction with a surgical access may result in substantial regeneration of root cementum, periodontal ligament, and bone, thus improving the clinical outcomes in intrabony, recession, and Class II furcation defects.
Comprehensive Periodontal Regenerative Care: Combination Therapy Involving Bone Allograft, a Biologic, a Barrier, and a Subepithelial Connective Tissue Graft to Correct Hard‐ and Soft‐Tissue Deformities
Authors: Rosen Paul S.
Published: April 2012

Type of Case: A 70‐year‐old white female was referred for evaluation and treatment of isolated periodontal lesions throughout her mouth. Her chief concern was the soft‐tissue deformity that was present on her maxillary right canine. Radiographic evaluation of this area revealed that, along with this mucogingival defect, there was an intrabony lesion that required treatment.

Case Presentation: The ability to enhance the prognosis and appearance of this tooth by restoring the hard‐tissue support and soft‐tissue profile in the same procedure has rarely been reported in the literature. This case report focuses on a layered approach that simultaneously addresses both aspects of the patient's problem. Treatment involved a mineralized allograft, a biologic agent, an amnion–chorion barrier, and a subepithelial connective tissue graft on a root treated with tetracycline.

Conclusions: The clinical and radiographic results at 6 months suggest a very favorable result. Efforts to treat teeth that have both hard‐ and soft‐tissue deformities should consider combination therapies that address both concerns.
Intravenous Bisphosphonates for Osteoporosis and Implant Placement
Authors: Reddy Michael S. , Geisinger Maria L. , Liu Perng‐Ru , Holmes Carolyn M. , Vassilopoulos Philip J. , Geurs Nicolaas C.
Published: April 2012

Focused Clinical Question

In a patient receiving intravenous infusion of nitrogen containing bisphosphonates for management of osteoporosis, is surgical implant treatment contraindicated because of the risk of impaired bony wound healing and osteonecrosis of the jaw?

Clinical Scenario

A 64‐year‐old postmenopausal woman who leads a busy life and works full time as a business executive presents with a fracture of her maxillary central incisors teeth #8 and #9. She has been a periodontal maintenance patient for the past 20 years with excellent oral hygiene. One month earlier, she experienced trauma to her anterior teeth by walking into a closed patio door. She appears younger than her stated age, and her overall health is good except for a history of postmenopausal osteoporosis diagnosed using a bone mineral density evaluation with a T‐score at lumbar spine of −2.6. Currently, her only medication is a yearly intravenous infusion of zoledronic acid, which she has received for the past 3 years. The reason for this visit is to inform her that the teeth have a hopeless prognosis based on the progressive symptoms and will need to be extracted, and to discuss treatment options, risks, benefits, and alternatives.
Systemic Teriparatide Administration Promotes Osseous Regeneration of an Intrabony Defect: A Case Report
Authors: Bashutski Jill D. , Kinney Janet S. , Benavides Erika , Maitra Samopriyo , Braun Thomas M. , Giannobile William V. , McCauley Laurie K. , Eber Robert M.
Published: April 2012

Introduction: Teriparatide comprises the first 34 amino acids of parathyroid hormone and is a systemic anabolic agent that is Food and Drug Administration approved for the treatment of osteoporosis but not for periodontitis. To our knowledge, this is the first clinical case report to document the treatment of a patient with severe periodontitis using an open‐flap debridement procedure in conjunction with teriparatide.

Case Presentation: A 45‐year‐old female patient was diagnosed with severe chronic periodontitis, including the presence of an intrabony defect on tooth #6. She received open‐flap debridement surgery in conjunction with daily systemic administration of 20 μg teriparatide, oral vitamin D, and calcium supplements for 6 weeks. Radiographic, clinical, gingival crevicular fluid (pyridinoline cross‐linked carboxy‐terminal propeptide of type I procollagen, procollagen type 1 N‐propeptide, and osteocalcin), and serum parameters (parathyroid hormone, bone alkaline phosphatase, calcium, and 25‐hydroxyvitamin D) were assessed. Treatment outcomes were evaluated over 4 years, with successful radiographic and clinical results throughout the follow‐up period.

Conclusion: Teriparatide administration in conjunction with traditional open‐flap debridement surgery offers potential for the treatment of severe intrabony defects resulting from chronic periodontitis.
A Novel Adjuvant Treatment to Scaling and Root Planing With a Topical Gingival Patch: A Case Series
Authors: Saffer Aron , Samuels Noah
Published: April 2012

Introduction: Gingival inflammation often persists despite conventional therapies. A topical gingival patch containing natural extracts has been shown in a randomized clinical trial to reduce gingival inflammation when administered as an independent therapy. We report a case series of patients with moderate‐to‐severe chronic periodontitis in whom the patch was used together with scaling and root planing (SRP).

Case Series: A series of 20 healthy patients presenting with moderate‐to‐severe chronic periodontitis (probing depths, 5 to 8 mm) were treated with the patch immediately after treatment with SRP. All patients had bilateral gingival inflammation with a gingival index (GI) ≥2 and bleeding on probing (BOP) on ≥1 site per tooth on two adjacent teeth. After SRP, the patch was applied first by the study periodontist (AS), with two subsequent applications over the next 24 hours by the patient, and reevaluated 2 to 4 weeks later. On a separate visit, the contralateral side was treated with SRP alone and was also reassessed after 2 to 4 weeks. Both the patch and non‐patch sides showed improvement after SRP. When comparing the two sides, the patch‐treated area showed a significantly greater reduction of inflammation and bleeding, as measured by GI (P <0.001) and BOP (P <0.002).

Conclusions: In this case series, the patch is shown to provide a beneficial effect by helping to further reduce inflammation when used in conjunction with scaling and root planing. Additional research of the patch combined with SRP treatment is warranted within the framework of large randomized and controlled trials.
Ligneous Periodontitis and Conjunctivitis With Hyper‐Immunoglobulin E Syndrome
Authors: Gupta Shalini R. , Chaudhry Zainab , Kumar Vijay , Saran Ravindra Kumar , Augustine Jeyaseelan
Published: April 2012

Introduction: Hyper‐immunoglobulin E syndrome (HIES) is a rare multisystem primary immunodeficiency caused by mutation in signal transducer and activator of transcription gene protein 3, associated with recurrent skin and sinopulmonary infection and high serum levels of immunoglobulin E (IgE). It is mostly sporadic, but familial inheritance with autosomal dominant and autosomal recessive forms are seen. Ligneous periodontitis and conjunctivitis are rare poorly defined conditions, characterized by pseudomembranous inflammation of mucosa. There is accumulation of fibrin in lamina propria mostly as a result of quantitative plasminogen deficiency.

Case Presentation: An 18‐year‐old Indian girl with history of newborn rash had generalized pseudomembranous periodontitis, bilateral pseudomembranous conjunctivitis, multiple staphylococcal abscesses on the feet, right radial neck fracture after minor trauma, eosinophilia, and raised IgE. Subepithelial deposition of fibrin was seen in gingival and conjunctival biopsies. The National Institutes of Health scoring system for HIES was calculated to be 42 (HIES score >40 points indicates that the presence of autosomal dominant HIES genotype is highly likely). Segmental gingivectomies, topical heparin, and corticosteroids were not effective in dentate areas of gingiva, whereas edentulous areas healed normally. Oral and topical antibiotics caused resolution of the skin abscesses, whereas lubricating and corticosteroid eye drops caused improvement in conjunctival lesions.

Conclusions: Ligneous periodontitis and conjunctivitis are novel manifestations in HIES recalcitrant to various treatments. Optimal therapy would be systemic plasminogen concentrate replacement, which is not commercially available. Extensive investigations and a multidisciplinary approach to diagnosis and management are required.
Periodontal Healing of a Human Intrabony Defect Treated by Autogenous Periosteal Barrier Membrane and Bone Graft: A Clinical and Histologic Case Report
Authors: Femminella Beatrice , Traini Tonino , Romano Luigi , Di Tullio Marcella , D'Arcangelo Camillo , Paolantonio Michele
Published: April 2012

Introduction: The aim of this case report is to clinically and histologically evaluate the healing of a deep intrabony defect treated with a combination therapy using autogenous periosteal membrane and autogenous bone graft.

Case Presentation: A 45‐year‐old female was scheduled for hemisection of tooth #30, affected by a degree III furcation involvement, with the extraction of the mesial root. The root was associated with a 6‐mm intrabony defect. The patient volunteered to have the defect treated by a regenerative technique before the extraction. A notch was placed at the level of the crestal bone on the root surface to serve as reference for histologic evaluation. The intrabony defect was filled by autogenous bone chips and covered by an autogenous periosteal barrier membrane obtained from the palate. One year after regenerative treatment, a block biopsy containing the root with some of the surrounding soft and hard tissues was sampled during the tooth hemisection procedure and processed for histologic evaluation. At the 12‐month examination, a 7‐mm probing depth decrease and a 4‐mm clinical attachment gain were observed. The radiographic examination showed the complete filling of the defect. Histologic evaluation showed the formation of new cellular cementum with inserting collagen fibers from the base of the defect to the notch level. Newly formed bone was also observed.

Conclusion: Our results suggest that the adjunctive use of autogenous bone graft and periosteal barrier membrane may represent a promising surgical technique for periodontal regeneration in clinical practice.
Treatment Alternative for Root Resorption of an Avulsed Tooth in a Growing Child: A Case Report With a 4‐Year Follow‐Up
Authors: Mau Lian Ping , Pang Iok‐Chao , Tseng Chuen‐Chyi , Melody Chen Yea‐Huey , Cochran David L.
Published: April 2012

Introduction: Dental treatment is difficult in young patients who present with a root‐resorbed permanent tooth and are still growing. The purpose of this case report is to present a treatment option to delay implant placement until the child's growth has slowed and the tissues are fully developed so that an esthetic implant restoration can be achieved.

Case Presentation: A 9‐year‐old female patient presented to the clinic after a traffic accident. Avulsion of her maxillary right central incisor had occurred and the tooth was repositioned during that emergency visit. The tooth vitality was followed regularly. Significant root resorption of the tooth was observed 4 years after the accident. The treatment strategy was to retain the tooth as long as possible until her growth was completed. Root canal therapy was done, and the canal was sealed with calcium hydroxide, mineral trioxide aggregate, and glass ionomer cement. Unfortunately, root resorption continued. When the patient was 22 years old, the tooth was extracted, and a standard‐sized implant was placed immediately with a bone graft, collagen membrane, and connective tissue graft augmentation. A temporary restoration was inserted 5 months after implantation. The definitive restoration was fabricated 3 months after the provisional. The dentists and patient were satisfied with the final outcome.

Conclusion: Repositioning of an avulsed tooth and conservative endodontic treatment despite root resorption preserved the adjacent bone in a young female until her growth was complete, allowing for the placement of a standard‐sized dental implant with a natural esthetic restoration.
The Sandwich Bone Augmentation Technique
Authors: Fu Jia‐Hui , Wang Hom‐Lay
Published: April 2012

Introduction: Horizontal ridge width reduction after tooth extraction is a common clinical scenario. As such, when implant‐supported restorations are planned for tooth replacement, it is a challenge to regenerate adequate bone width to house the dental implant and ensure its long‐term stability. Several horizontal ridge augmentation techniques, e.g. guided bone regeneration, ridge splitting, and block grafts, have been tested and proven to predictably augment bone width. Although these techniques are successful, treatment time is significantly increased and patients need to endure additional surgical procedures. Therefore, this case report aims at illustrating the ease and success of the sandwich bone augmentation technique when performed with dental implant placement.

Case Presentation: A clinical case with a horizontally deficient ridge was selected. A buccal dehiscence was observed after placement of the dental implant in a prosthetically driven position. Autogenous bone graft harvested from the osteotomy site was placed on the exposed implant surface. Mineralized cancellous bone allograft was layered on, followed by a layer of mineralized cortical bone allograft. A collagen membrane was trimmed and used to contain the bone grafts as well as to exclude unwanted cells, such as epithelial cells and connective tissue fibroblasts. Tension‐free primary closure was subsequently obtained. Six months later, mature regenerated bone was found on the buccal surface of the implant at surgical reentry.

Conclusion: Simultaneous implant placement with the sandwich bone augmentation technique predictably regenerated bone on implant buccal dehiscence defects.