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Biomedical subjects

Sebastiano Andreana

Publications and source records attributed to Sebastiano Andreana.

18 recordsLinked to original sources

The effect of EDTA in attachment gain and root coverage.

Root surface biomodification using low pH agents such as citric acid and tetracycline has been proposed to enhance root coverage following connective tissue grafting. The authors hypothesized that root conditioning with neutral pH edetic acid would improve vertical recession depth, root surface coverage, pocket depth, and clinical attachment levels. Twenty teeth in 10 patients with Miller class I and II recession were treated with connective tissue grafting. The experimental sites received 24% edetic acid in sterile distilled water applied to the root surface for 2 minutes before grafting. Controls were pretreated with only sterile distilled water. Measurements were evaluated before surgery and 6 months after surgery. Analysis of variance was used to determine differences between experimental and control groups. We found significant postoperative improvements in vertical recession depth, root surface coverage, and clinical attachment levels in test and control groups, compared to postoperative data. Pocket depth differences were not significant (P<.01).

Adult↗

Toothbrush abrasions and noncarious cervical lesions: evolving concepts.

Toothbrush abrasion at the cervical areas of teeth is generally thought to be a result of frequent or forceful toothbrushing, faulty or vigorous technique, filament stiffness or design, dominant hand dexterity, or abrasive dentifrices. However, a review of the evidence-based literature cannot conclusively establish any one factor as the primary etiology of cervical abrasions because of inherent methodological limitations and conflicting results. Rather, a variety of factors related to toothbrushing may act in concert with dental erosion and, possibly, occlusal loading in the creation of noncarious cervical lesions. Individual variation also may make some individuals more susceptible to development and may modify the progression of those lesions. Individual variations may involve oral and dental anatomy, periodontal status or phenotype, and periodontal disease history and treatment. Further research is needed to clearly assess the interaction of all those factors in the development of cervical lesions. Therefore, awareness of a multifactorial etiology in noncarious cervical lesions may help the clinician to formulate an appropriate treatment plan for the patient.

Acids↗

Maxillary sinus elevation for implant placement using calcium sulfate with and without DFDBA: six cases.

Maxillary sinus lift is a surgical procedure performed to increase the volume of bone mass so that dental implants can be placed in the maxillary arch. Several materials have been suggested to be used for this procedure. The purpose of this study was to present the clinical and histologic results of using calcium sulfate with and without demineralized freeze-dried bone allograft (DFDBA) in sinus lift. Medical-grade sterile calcium sulfate was used alone or in combination with DFDBA in 6 patients undergoing sinus lift surgery for implant placement. Bone biopsies were taken at different times ranging from 6 to 24 months. All samples examined showed bone growth with some possible remnants of the grafted DFDBA. Implants were inserted either at the time of the lift or 6 months later. All of them were secure with primary stability. The cases reported indicate that calcium sulfate can be successfully used alone or in combination with DFDBA for sinus lift procedures and that possible residues of DFDBA can be found within newly generated bone. (Implant Dent 2004;13:270-277)

Adult↗

Effect of enamel matrix derivative (Emdogain) on bone defects in rabbit tibias.

The aim of this study was to assess the effect of an enamel matrix derivative (Emdogain, Biora, AB, Malmö, Sweden) on bone healing. Ten New Zealand rabbits, weighing about 2.5 kg, were used. One 8-mm bone defect was created in each tibia. The defect on the right leg was filled with Emdogain, whereas the defect on the opposite leg was left unfilled as control. A total of 20 defects were created. Five rabbits each were killed at 4 and 8 weeks with an overdose of Tanax. Block sections containing the defects were retrieved and the specimens processed for light microscopy examination. The slides were stained with acid and basic fuchsin and toluidine blue. Histologically, no differences were noted in both groups at each observation period; in the test group, remnants of the implanted Emdogain were not present at 4 weeks. Newly formed bone was detectable in both groups at all observation times. At 8 weeks, both groups showed mature bone, and in the test group the material implanted was not visible. No inflammatory cells were visible in both groups. In conclusion, our results indicate that Emdogain implanted in bone defects is fully resorbed after 4 to 8 weeks and does not adversely affect bone formation.

Animals↗

An assessment of stress analyses in the theory of abfraction.

Wedged-shaped lesions at the cemento-enamel junction of teeth have been attributed primarily to biomechanical loading forces that cause flexure and failure of enamel and dentin. This theory, termed abfraction, remains controversial. This review examined studies on mechanical properties of enamel and dentin and studies on bite forces and mastication as background information. Abfraction is based principally on a few early finite element analysis and photoelastic models showing stress concentration at the dental cervical area without actually showing enamel and dentin fracture. However, a review of more recent dental stress analyses has been contradictory. Particularly, analyses of the periodontal ligament and alveolar bone, not modeled in previous studies, have shown that those structures may dissipate occlusal loading forces from the cervical areas. In addition, some models may not fully represent intricate dental anatomy and complex occlusal function. Therefore, the key basis of the abfraction theory may be flawed.

Animals↗

Wedged cervical lesions produced by toothbrushing.

PURPOSE: To compare the morphology of experimentally induced cervical toothbrush abrasion lesions to teeth demonstrating non-carious cervical lesions in vivo. METHODS: Eighteen premolars extracted for orthodontic reasons were each subjected to 80 hours (1.4 million strokes) of horizontal brushing in a custom fabricated toothbrushing machine. Toothpaste slurry was applied continuously and specimens were subjected to 300 gms of toothbrushing force. Denture base resin was used to simulate gingival recession of 1 mm and a sulcus width of 0.1 mm. Cervical abrasions were analyzed by optical and scanning electron microscopy and classified as either V-shape/wedged vs. U-shape/rounded lesions. When lesions exhibited both shapes, they were classified as mixed. Shapes of experimentally induced lesions then were compared to naturally occurring ones found on extracted premolars. RESULTSts: Experimentally induced toothbrush abrasion duplicated the classical clinical shapes. Half (9/18) of the experimentally induced toothbrush abrasions exhibited wedged lesions, 28% (5/18) showed a mixed wedged/rounded lesion, and 22% (4/18) showed rounded lesions. Serial photography showed progression of the morphology of the lesions. Toothbrush abrasion apparently begins apical to the cemento-enamel junction, progresses to dentin, and then undermines enamel with loss of the original cemento-enamel junction. Wedged lesions may appear with the apex oriented coronal or apical, or may be symmetrical.

Bicuspid↗

Crown lengthening: basic principles, indications, techniques and clinical case reports.

Sometimes, in order to properly restore teeth, surgical intervention in the form of a crown-lengthening procedure is required. Crown lengthening is a periodontal resective procedure, aimed at removing supporting periodontal structures to gain sound tooth structure above the alveolar crest level. Periodontal health is of paramount importance for all teeth, both sound and restored. For the restorative dentist to utilize crown lengthening, it is important to understand the concept of biologic width, indications, techniques and other principles. This article reviews these basic concepts of clinical crown lengthening and presents four clinical cases utilizing crown lengthening as an integral part of treatments, to restore teeth and their surrounding tissues to health.

Alveolar Process↗

Cellular inflammatory response to porcine collagen membranes.

OBJECTIVES: The purpose of this study was to assess local inflammatory changes associated with the implantation of three different porcine collagen membranes having potential use in periodontal regeneration. METHODS: Materials were implanted subcutaneously into prepared sites along the dorsal skin surface of 60 female Wistar rats. Saline and turpentine were used as negative and positive controls, respectively. Animals were killed and biopsies obtained after 3 d, and at 1, 2, 4, 6, and 8 weeks after membrane implantation. A panel of six monoclonal antibodies was used to identify circulating monocytes (ED1), resident tissue macrophages (ED2), lymphoid macrophages (ED3), Ia-antigen expression (OX6), T-lymphocytes (OX19), and B-lymphocytes (OX33). Cells identified by each antibody were subjected to quantitative immunocytochemistry to compare any differences present among groups. Sera obtained 8 weeks after grafting were used in immunoblotting assays to detect the presence of systemic antiporcine antibodies. RESULTS: We found that the mononuclear cell subsets associated with implantation of porcine collagen membranes were similar to those obtained with saline administration. On the other hand, the use of turpentine resulted in an inflammatory infiltrate characterized by significantly higher numbers of all six monoclonal cell subsets at all time periods evaluated, compared to either saline or any of the membranes (P < 0.001). CONCLUSIONS: The collagen membranes do not appear to be associated with a significant local inflammatory response, nor a systemic immune response, and thus appear to be well tolerated, rendering them useful in periodontal regeneration.

Analysis of Variance↗

Toothbrushing and gingival recession.

AIM: To review the hypothesis that toothbrushing leads to gingival recession. Gingival recession develops due to anatomical and pathological factors. The prevalence of recession is dependent on the age and characteristic of the population because it usually presents in individuals with periodontal disease or those who practise zealous or improper oral hygiene methods. Gingival trauma and gingival abrasion from toothbrushing is thought to progress directly to gingival recession. Case studies documenting recession from toothbrush trauma are speculative. Short-term studies suggest that gingival trauma and gingival abrasion may result from toothbrushing, but the direct relationship between traumatic home care and gingival recession is inconclusive. Long-term studies remain elusive or do not support the development of recession following toothbrushing. Nevertheless, tooth abrasion may be an integral part in the aetiology of recession. Toothbrush abrasion also may cause wear at the cemento-enamel junction resulting in the destruction of the supporting periodontium leading to recession.

Gingival Recession↗

Noncarious cervical lesions and abfractions: a re-evaluation.

BACKGROUND: The concept of abfraction is controversial. The authors present the fundamental basis of abfraction and review studies that describe the condition. TYPES OF STUDIES REVIEWED: The authors used data on masticatory forces, enamel and dentin properties, as well as stress studies related to abfraction, for background information. They also analyzed the genesis of the abfraction theory, experimental evidence, case presentations, clinical investigations and restorative studies. RESULTS: The theory of abfraction is based primarily on engineering analyses that demonstrate theoretical stress concentration at the cervical areas of teeth. While some recent stress studies support earlier findings, others have provided significant deviating information. Few controlled studies exist that demonstrate the relationship between occlusal loading and abfraction lesions. The role of occlusal loading in noncarious cervical lesions (as shown by clinical data) appears to be part of a multifactorial event that may not necessarily follow the proposed classic abfraction mechanism, and other mechanisms or factors may explain cervical restoration failure just as well. CLINICAL IMPLICATIONS: There is little direct evidence supporting the theory of abfraction as the primary factor in the formation of noncarious cervical lesions. Controlled clinical trials are necessary to elucidate more fully the etiology of those lesions.

Bite Force↗

Simultaneous treatment of multiple, bilateral, deep buccal recession defects with bioabsorbable barrier membranes: a case report.

Gingival recessions are of concern both esthetically and functionally for the dental patient. Bioabsorbable barriers were used to simultaneously treat six mucogingival recessions affecting six teeth in both maxillary quadrants of a 34-year-old woman. Root exposures ranging from 4 to 6 mm were successfully treated; complete root coverage was obtained at all treated sites. Follow-up visits up to 18 months revealed the stability of the clinical outcome, confirming the efficacy of the procedure.

Absorbable Implants↗

Tooth wear: attrition, erosion, and abrasion.

Attrition, erosion, and abrasion result in alterations to the tooth and manifest as tooth wear. Each classification acts through a distinct process that is associated with unique clinical characteristics. Accurate prevalence data for each classification are not available since indices do not necessarily measure one specific etiology, or the study populations may be too diverse in age and characteristics. The treatment of teeth in each classification will depend on identifying the factors associated with each etiology. Some cases may require specific restorative procedures, while others will not require treatment. A review of the literature points to the interaction of the three entities in the initiation and progression of lesions that may act synchronously or sequentially, synergistically or additively, or in conjunction with other entities to mask the true nature of tooth wear, which appears to be multifactorial.

Acids↗

Engineering a bioactive matrix by modifications of calcium sulfate.

The goal of this study was to define the conditions for the fabrication of a bioactive matrix that induces and supports cell proliferation and tissue regeneration. The proposed hypothesis was that a composite graft could be engineered by the absorption of platelet-rich plasma (PRP) onto calcium sulfate (CS). Evaluation of the biological activity of the engineered grafts was based on osteoblast proliferation studies and scanning electron microscopy (SEM) analyses. Graft samples were created in a standard size and shape so that the surface available for attachment and cell proliferation was always identical. Proliferation data were expressed as counts per minute per group and differences among groups were statistically analyzed by analysis of variance followed by the Scheffé test (alpha = 0.1). SEM analysis showed that the combination of CS and PRP presents a preserved crystalline structure well integrated by organic matrix. This combination showed the highest cell proliferation levels (p < 0.001). Further evaluations demonstrated that PRP is activated when combined with CS. When tested as a possible carrier for biologically active molecules such as platelet-derived growth factor (PDGF), CS showed increased cell proliferation (p < 0.001). SEM revealed adherent osteoblasts with broad flattened edges on CS-PRP. This study proposes CS as an efficient carrier for PRP or PDGF and supports the use of these combinations as bioactive matrices in clinical or laboratory applications.

Calcium Sulfate↗

Collagen: an overview.

Collagen is a versatile material with biological properties that make it useful for the fabrication of implantable devices in medicine and dentistry. In this article we review collagen biosynthesis, structure, and types, as well as the properties that make it compatible with human tissues.

Amino Acid Sequence↗

Collagen as an implantable material in medicine and dentistry.

Collagen is a highly versatile material, extensively used in the medical, dental, and pharmacological fields. Collagen is capable of being prepared into cross-linked compacted solids or into lattice-like gels. Resorbable forms of collagen have been used to dress oral wounds, for closure of graft and extraction sites, and to promote healing. Collagen-based membranes also have been used in periodontal and implant therapy as barriers to prevent epithelial migration and allow cells with regenerative capacity to repopulate the defect area. It has been hypothesized that membrane regenerative techniques facilitate the natural biological potential by creating a favorable environment for periodontal and peri-implant regeneration. Due to the enormous potential of collagen-based regenerative barriers, clinicians may benefit from a review of potential applications of implantable collagen and knowledge of collagen preparation and membrane types as well as from as awareness of the functional and degradation properties of those materials.

Absorbable Implants↗

Risk and prevention of transmission of infectious diseases in dentistry.

Health care providers are at risk for infection with bloodborne pathogens, including hepatitis B virus, human immunodeficiency virus, and hepatitis C virus. Recommended infection control practices are applicable to all settings in which dental treatment is provided. Dentists remain at low risk for occupationally acquired human immunodeficiency virus. Dental health care workers, through occupational exposure, may have a 10 times greater risk of becoming a chronic hepatitis B carrier than the average citizen. Tuberculosis is caused by Mycobacterium tuberculosis. In general, persons suspected of having pulmonary or laryngeal tuberculosis should be considered infectious if they are coughing, are undergoing cough-inducing or aerosol-generating procedures, or have sputum smears positive for acid-fast bacilli. Although the possibility of transmission of bloodborne infections from dental health care workers to patients is considered to be small, precise risks have not been quantified by carefully designed epidemiologic studies. Emphasis should be placed on consistent adherence to recommended infection control strategies, including the use of protective barriers and appropriate methods of sterilization or disinfection. Each dental facility should develop a written protocol for instrument reprocessing, operatory cleanup, and management of injuries. Such efforts may lead to the development of safer and more effective medical devices, work practices, and personal protective equipment.

Blood-Borne Pathogens↗

Using a diode laser to uncover dental implants in second-stage surgery.

A soft tissue diode laser offers an alternative technique for uncovering dental implants. This article presents two cases in which four dental implants were uncovered using a soft tissue laser. This technique provides an efficient and patient-friendly method to perform second-stage implant surgery, safely allowing a faster rehabilitative phase.

Dental Abutments↗