Biomedical subjects

Phillip J Sheridan

Publications and source records attributed to Phillip J Sheridan.

12 recordsLinked to original sources

PubMed2005

Influence of platelet-rich plasma added to xenogeneic bone grafts in periimplant defects: a vital fluorescence study in dogs.

BACKGROUND: The use of platelet-rich plasma (PRP) has been suggested in order to increase the rate of bone deposition when sites are augmented prior to or in conjunction with dental implant placement. PURPOSE: The goal of this study was to investigate whether the addition of PRP to xenogeneic bone grafts would increase the rate of bone formation in dogs. MATERIALS AND METHODS: Ninety endosseous dental implants were inserted in the mandibles of nine hound dogs. Subsequently, mesial and distal three-wall periimplant defects were surgically created. Defects were randomly assigned to three groups: demineralized freeze-dried bone graft plus platelet-rich plasma (DFDBG plus PRP), demineralized freeze-dried bone graft alone (DFDBG), and no treatment. Postsurgically each dog received a series of three fluorescent labels for estimation of bone cell activity at baseline and during different stages of healing, with particular attention to the bone formation rate per tissue volume (BFR/TV). Animals were sacrificed at 1 month, 2 months, and 3 months, and specimens were subjected to analysis by fluorescence microscopy. Treatment effects were evaluated with analysis of variance models. RESULTS: Overall, the average BFR/TV differed by treatment although this difference approached only minimal statistical significance (p = .057). The largest difference occurred between periimplant defects treated with DFDBG only and defects that were not treated (mean percentage BFR/TV, 0.0720% vs 0.0994%). There was no evidence of an overall treatment effect (p = .27) for the mineral apposition rate (MAR) values. The data also suggest a consistent variability in the bone formation parameters among the three groups at different healing points. CONCLUSION: In this animal model the addition of PRP to xenogeneic bone grafts did not demonstrate evidence of faster bone formation during healing. However, limitations of the histologic technique possibly played a negative role in the assessment of bone formation parameters.

Alveolar Ridge Augmentation↗

PubMed2005

Regenerative potential of platelet-rich plasma added to xenogenic bone grafts in peri-implant defects: a histomorphometric analysis in dogs.

BACKGROUND: The purpose of this investigation was to evaluate the regenerative influence of platelet-rich plasma (PRP) added to xenogenic bone grafts on bone histomorphometric parameters in a dog model. METHODS: Ninety endosseous dental implants were inserted in the mandibles of nine hound dogs. Mesial and distal 3-wall peri-implant defects were surgically created adjacent to the implants. Defects were randomly assigned to three groups: demineralized freeze dried bone with platelet-rich plasma (DFDB + PRP), DFDB alone, and no treatment (NT). Animals were sacrificed at 1, 2, and 3 months according to a previously established randomization schedule, and specimens were subjected to histomorphometric analysis. Percentages of bone area inside the implant threads (BiIT), bone-to-implant contact (BIC), and bone area outside implant threads (BoIT) were recorded. Treatment effects were evaluated using analysis of variance models. RESULTS: The effect of the three treatments on the outcome measures did not differ significantly by healing time (P > 0.05 for the healing time by treatment interaction). However, the average (standard deviation) percentage of BIC and BoIT was significantly different between the treatment groups. In particular, the average percentage of BIC differed between peri-implant defects treated with DFDB + PRP (33.8% [11.0]) and those treated with DFDB alone (28.5% [10.8]; P = 0.042), as well as those in the NT group (27.9% [11.0]; P = 0.024). Furthermore, the average percentage of BoIT differed significantly between defects treated with DFDB + PRP compared to defects in the NT group (51.6% [12.2] versus 43.3% [10.3]; P = 0.005). There was borderline evidence to suggest that the average percentage of BiIT and BIC was significantly different depending on the length of the healing time (P = 0.054 and P = 0.085, respectively). CONCLUSION: This study found that the addition of PRP to xenogenic bone grafts demonstrated a low regenerative potential in this animal model.

Alveolar Bone Loss↗

PubMed2004

Tetracycline and other tetracycline-derivative staining of the teeth and oral cavity.

Tetracyclines (TCN) were introduced in 1948 as broad-spectrum antibiotics that may be used in the treatment of many common infections in children and adults. One of the side-effects of tetracyclines is incorporation into tissues that are calcifying at the time of their administration. They have the ability to chelate calcium ions and to be incorporated into teeth, cartilage and bone, resulting in discoloration of both the primary and permanent dentitions. This permanent discoloration varies from yellow or gray to brown depending on the dose or the type of the drug received in relation to body weight. Minocycline hydrochloride, a semisynthetic derivative of tetracycline often used for the treatment of acne, has been shown to cause pigmentation of a variety of tissues including skin, thyroid, nails, sclera, teeth, conjunctiva and bone. Adult-onset tooth discoloration following long-term ingestion of tetracycline and minocycline has also been reported. The remarkable side-effect of minocycline on the oral cavity is the singular occurrence of "black bones", "black or green roots" and blue-gray to gray hue darkening of the crowns of permanent teeth. The prevalence of tetracycline and minocycline staining is 3-6%. The mechanism of minocycline staining is still unknown. Most of the reviewed literature consisted of case reports; longitudinal clinical trials are necessary to provide more information on the prevalence, severity, etiology and clinical presentation of tetracycline and TCN-derivative staining in the adult population.

Anti-Bacterial Agents↗

PubMed2004

Desquamative gingivitis associated with IgG/IgA pemphigoid presents a challenging diagnosis and treatment: a case report.

BACKGROUND: Mucous membrane pemphigoid (MMP) is a heterogeneous group of autoimmune blistering disorders characterized by subepithelial separation and the deposition of immunoglobulins and complement along the basement membrane zone (BMZ). This disease is diagnosed with direct immunofluorescence testing showing a linear deposition of immunoglobulins and/or complement along the BMZ and indirect immunofluorescence testing showing circulating IgG (and sometimes IgA) autoantibodies along the BMZ. In this case report we describe desquamative gingivitis secondary to IgG/IgA pemphigoid and the management of this challenging variant of MMP. METHODS: Routine histology, direct immunofluorescence testing, and indirect immunofluorescence testing were utilized and correlated to the clinical findings to diagnose this unusual immunobullous disease. RESULTS: Direct and indirect immunofluorescence testing confirmed the clinical diagnosis of IgG/IgA pemphigoid as the cause of desquamative gingivitis and the other mucosal findings in this patient. A treatment program including dapsone and other drugs completely resolved the oral lesions after 14 months of therapy. CONCLUSIONS: Desquamative gingivitis associated with IgG/IgA pemphigoid can be challenging to diagnose and treat. After 14 months of treatment, a combination therapy consisting of dapsone with cimetidine and vitamin E to enhance drug efficacy and frequent intramuscular administrations of triamcinolone achieved control of both the oral and genital elements of IgG/IgA pemphigoid in this patient.

Aged↗

PubMed2004

Successful treatment of oral lichen planus-like chronic graft-versus-host disease with topical tacrolimus: a case report.

BACKGROUND: Bone marrow transplantation (BMT) is a common treatment used for deficiencies of host marrow or in the control of blood malignancies. Post-allogeneic BMT complications include graft-versus-host disease (GVHD). GVHD occurs when immunologically active T lymphocytes are transplanted into an immunosuppressed recipient who is genetically disparate from the donor. In this case report we describe the occurrence of oral lichen planus-like lesions as the first manifestation of chronic GVHD (c-GVHD) and the subsequent management of this disease with topical tacrolimus. METHODS: Diagnostic aids included routine histology and direct immunofluorescence studies to rule out immunobullous diseases and to confirm the c-GVHD. Treatment consisted of topical application of 0.1% tacrolimus ointment three times a day. RESULTS: Routine histology confirmed the clinical diagnosis of oral lichen planus-like c-GVHD. Treatment with tacrolimus ointment completely resolved the oral lesions after 2 months of therapy. CONCLUSIONS: Topical tacrolimus at low concentrations (0.1%) shows promise in the management of oral lichen planus-like c-GVHD. Controlled studies are necessary to assess the efficacy, the duration of therapy required for effective results, and the safety of this treatment over the long-term.

Administration, Topical↗

PubMed2004

Assessment of peripheral dual-energy x-ray absorptiometry measurements in peri-implant bone defects in dogs.

BACKGROUND: The goal of this study was to assess the variability of peripheral dual-energy x-ray absorptiometry (pDEXA) measurements in peri-implant bone defects in dogs. METHODS: Ninety dental implants were inserted in edentulous areas of nine foxhound dogs and standardized peri-implant bone defects were created on the mesial and distal aspect of each fixture (N = 144 total). The animals were sacrificed at 1, 2, and 3 months, respectively. Bone mineral density measurements (BMD) were performed with the use of pDEXA. The calibration of the system was determined by generating four quality control plots using a phantom of known density value. A series of three repeated measurements of the peri-implant sites were made with repositioning of the region of interest. The measurements were performed at the mesial and distal peri-implant sites. The variability of the three BMD measurements was expressed as the coefficient of variation (CV), which is calculated as ([SD/mean] x 100). The difference in the CV between the mesial and distal sites was evaluated using an analysis of variance model for repeated measures accounting for timing of sacrifice (month 1, 2, 3), dog (1 through 9), side (left, right), and adjacent defect regions between implants (1 through 4). RESULTS: The calibration of the pDEXA measured by means of the phantom resulted in a deviation of 0.17%, 0.52%, -0.17%, and 0.00%, respectively, for each of the four assessments. The average CV for the 72 mesial and 72 distal peri-implant sites was 5.22% +/- 4.22% (median 3.50%; range 0.46% to 18.83%) and 5.37% +/- 3.54% (median 4.64%; range 0.22% to 15.35%), respectively. After accounting for timing of sacrifice, dog, side, and position, there was not a statistically significant difference in the CV between the mesial and distal peri-implant sites (P = 0.75). This indicates that the peri-implant site did not significantly affect the variability of the BMD measurements. CONCLUSIONS: This study demonstrated that the pDEXA is a non-invasive, convenient, and fast method to assess BMD around dental implants in animal studies. Limitations of the technique may have a negative impact in the precision of pDEXA when measuring small regions.

Absorptiometry, Photon↗

PubMed2004

Maternal chronic infection as a risk factor in preterm low birth weight infants: the link with periodontal infection.

In the past decade, there has been mounting scientific evidence suggesting that periodontal disease may play an important role as a risk factor for adverse pregnancy outcomes. This article focuses on the definition, incidence, risk factors associated with preterm low birthweight infants (PLBW), the evidence linking chronic infections and PLBW, and the scientific evidence linking periodontal infections with adverse pregnancy outcomes. Additionally, this review summarizes the current epidemiological studies on the PLBW/infection relation and makes conclusions based on these results. Data from a limited number of studies available support the hypothesis that periodontal disease may act as a risk factor for PLBW infants. The fetal exposure to different periodontal pathogens needs to be confirmed, the mechanisms associated with the potential passage of periodontal bacteria across the placental barrier, and the efficacy of different periodontal treatments in reducing the risk for PLBW need to be studied further.

Animals↗

PubMed2003

Denture sore mouth.

The majority of the lesions associated with DSM are preventable and can be managed successfully by the dental professional. The hyperplastic tissue response seen in denture wearing patients generally requires surgical excision and follow-up. Health care providers should be encouraged to ask patients to remove their prostheses during a thorough examination of the oral tissues. In addition, patients should be asked about the fit and comfort of their dentures, and referred to their dental health care team for appropriate follow-up when required.

Cheilitis↗

PubMed2003

Minocycline-induced staining of torus palatinus and alveolar bone.

BACKGROUND: Minocycline hydrochloride, an analog of tetracycline, is widely used in the treatment of acne. Its use has been associated with discoloration of teeth, bone, and other tissues. METHODS: A case is presented involving a patient with minocycline-induced staining of the torus palatinus and alveolar bone. RESULTS: No treatment was rendered since the patient was not concerned with the appearance of the discoloration. The patient's dermatologist elected to change antibiotics. CONCLUSIONS: Patients on long-term minocycline therapy should be made aware of the possibility of pigmentation of bone and soft tissue that may be reversible with discontinuation of therapy; however, minocycline-induced staining of the permanent dentition may not be reversible.

Acne Vulgaris↗

PubMed2002

Pyostomatitis vegetans as an early sign of reactivation of Crohn's disease: a case report.

BACKGROUND: The structures and lining of the oral cavity are an accessible mirror reflecting the health of an individual. They may play an important role in detecting and monitoring systemic diseases. Certain conditions that primarily affect other regions of the body may cause signs and symptoms in the mouth, either as the initial presenting symptom or in conjunction with other systemic manifestations. METHODS: Pyostomatitis vegetans, which occurred in a patient with a history of Crohn's disease, was diagnosed as an early sign of disease reactivation. RESULTS: The patient was treated with a topical fluorinated corticosteroid gel, which led to the improvement of the oral lesions. However, the oral lesions continued to recur over a period of several months until the underlying inflammatory bowel disease came under control. CONCLUSIONS: This report emphasizes the relationship of pyostomatitis vegetans to Inflammatory bowel disease and the importance of the oral lesions as initial presenting signs of systemic disease or activity.

Adult↗

PubMedDate not supplied

Is platelet-rich plasma the perfect enhancement factor? A current review.

Guided bone regeneration is an accepted surgical method employed in implant dentistry to increase the quantity and quality of the host bone in areas of localized alveolar defects. The lack of predictability in osseous regenerative procedures with various grafting materials suggests that improvement in the osteoinductive properties of these materials is highly desirable. Platelet-rich plasma (PRP), a modification of fibrin glue made from autologous blood, is being used to deliver growth factors in high concentration to sites requiring osseous grafting. Growth factors released from the platelets include platelet-derived growth factor, transforming growth factor beta, platelet-derived epidermal growth factor, platelet-derived angiogenesis factor, insulin-like growth factor 1, and platelet factor 4. These factors signal the local mesenchymal and epithelial cells to migrate, divide, and increase collagen and matrix synthesis. PRP has been suggested for use to increase the rate of bone deposition and quality of bone regeneration when augmenting sites prior to or in conjunction with dental implant placement Only 6 human studies using PRP have been found in the dental implant literature and 5 were case series or reports. Thus, there is clearly a lack of scientific evidence to support the use of PRP in combination with bone grafts during augmentation procedures. This novel and potentially promising technique requires well-designed, controlled studies to provide evidence of efficacy.

Alveolar Ridge Augmentation↗

PubMedDate not supplied

Influence of platelet-rich plasma added to xenogeneic bone grafts on bone mineral density associated with dental implants.

PURPOSE: The purpose of this study was to assess the bone mineral density changes after bone regeneration therapy using xenogeneic demineralized freeze-dried bone graft (DFDBG) plus platelet-rich plasma (PRP) and DFDBG alone in 3-wall peri-implant defects in dogs. MATERIALS AND METHODS: The mandibular premolars and molars of 9 adult hound dogs were removed surgically, and 90 sites were prepared for implant placement. Before implant placement, a total of 162 mesial and distal 3-wall peri-implant defects were surgically created. Defects were randomly assigned to three groups: DFDBG + PRP, DFDBG alone, and no treatment. Animals were sacrificed at 1, 2, and 3 months, and specimens were subjected to bone mineral density (BMD) and bone mineral content (BMC) analysis with a peripheral dual x-ray absorptiometry densitometer. RESULTS: The effect of treatment on BMD and BMC differed significantly by month of sacrifice (P = .030 and P = .035 for the month-by-treatment interactions, respectively). BMD differed significantly between peri-implant defects treated with DFDBG alone and untreated defects at 3 months (mean BMD of 0.6667 for DFDBG alone versus 0.5606 for untreated defects; P < .001). BMC also differed significantly between peri-implant defects treated with DFDBG alone and untreated defects at 3 months (mean BMC of 0.0276 for DFDBG alone versus 0.0236 for untreated defects; P = .001). No other pairwise comparison of the treatments within each month of sacrifice or at the overall treatment effect across all three months demonstrated significant differences. DISCUSSION: PRP has been proposed as an autogenous source of growth factors, which may increase the speed and completeness of healing. This study did not demonstrate a significant improvement in BMD or BMC when PRP was combined with DFDBG. Defects where grafting material was used, either with or without PRP, did demonstrate slightly greater BMD and BMC than those left untreated. CONCLUSION: This study found that the addition of PRP to xenogeneic bone grafts did not significantly alter BMD or graft maturity levels in this animal model.

Absorptiometry, Photon↗